vb.net – MaxVergelli.com

Render a Section in a Partial View – ASP.Net MVC

Max — Sun, 12 Apr 2020 15:34:00 +0000

Let’s start with the following configuration to give an example: in a MVC project, you have a “_Layout.vbhtml” file with this code



  
  
  
	
    
    @RenderSection("Scripts", false)

Then, you have a Partial View “ValidationScripts.vbhtml” in the Shared folder with

@Section Scripts
    
    
      
          
End Section

If you call the Partial View from a View like this…

@ModelType MvcExample.MyModel
@Code
    ViewData("Title") = "Test"
End Code

@Html.Partial("ValidationScripts")

Just a Test

However the Section “Scripts” is not rendered on the page, and the output HTML will be…

Solution

To render the Section in the Partial View, you need to create a couple of Extension methods like this:

public static class HtmlHelperExtensions
{
  private const string _jSViewDataName = "RenderJavaScript";
  private const string _styleViewDataName = "RenderStyle";

  public static void AddJavaScript(this HtmlHelper htmlHelper, 
                                   string scriptURL)
  {
    List scriptList = htmlHelper.ViewContext.HttpContext
      .Items[HtmlHelperExtensions._jSViewDataName] as List;
    if (scriptList != null)
    {
      if (!scriptList.Contains(scriptURL))
      {
        scriptList.Add(scriptURL);
      }
    }
    else
    {
      scriptList = new List();
      scriptList.Add(scriptURL);
      htmlHelper.ViewContext.HttpContext
        .Items.Add(HtmlHelperExtensions._jSViewDataName, scriptList);
    }
  }

  public static MvcHtmlString RenderJavaScripts(this HtmlHelper HtmlHelper)
  {
    StringBuilder result = new StringBuilder();

    List scriptList = HtmlHelper.ViewContext.HttpContext
      .Items[HtmlHelperExtensions._jSViewDataName] as List;
    if (scriptList != null)
    {
      foreach (string script in scriptList)
      {
        result.AppendLine(string.Format(
          "", 
          script));
      }
    }

    return MvcHtmlString.Create(result.ToString());
  }

  public static void AddStyle(this HtmlHelper htmlHelper, string styleURL)
  {
    List styleList = htmlHelper.ViewContext.HttpContext
      .Items[HtmlHelperExtensions._styleViewDataName] as List;

   if (styleList != null)
   {
     if (!styleList.Contains(styleURL))
     {
       styleList.Add(styleURL);
     }
   }
   else
   {
     styleList = new List();
     styleList.Add(styleURL);
     htmlHelper.ViewContext.HttpContext
       .Items.Add(HtmlHelperExtensions._styleViewDataName, styleList);
   }
 }

 public static MvcHtmlString RenderStyles(this HtmlHelper htmlHelper)
 {
   StringBuilder result = new StringBuilder();

   List styleList = htmlHelper.ViewContext.HttpContext
     .Items[HtmlHelperExtensions._styleViewDataName] as List;

   if (styleList != null)
   {
     foreach (string script in styleList)
     {
       result.AppendLine(string.Format(
         "", 
         script));
     }
   }

  return MvcHtmlString.Create(result.ToString());
  }
}

So, on any View or Partial View or Display/Edit Template you simply add what you need:

@{
  Html.AddJavaScript("http://cdn.jquerytools.org/1.2.7/full/jquery.tools.min.js");
}

Then, in your Layouts you render it where you want it! Like this markup…



  
  @Html.RenderStyles()
  @Html.RenderJavascripts()

vb.net Bitmap object locks images (impossible to move/delete jpg/gif files) – .Dispose() Method common problem

Max — Tue, 14 Jan 2020 15:47:04 +0000

Many people are in trouble and on forums asking why the .Net Bitmap object does not release an image with its .Dispose() method. The Bitmap object (after its destruction too) seems to lock the image file, then we are not able to move or delete that image file through the file system.

This is a known problem and it occurs when we declare and instantiate a Bitmap object and destruct that like in the following code:

[sourcecode language=”vb”]

‘create a bitmap object
Dim myBitmap As New Bitmap("c:myimage.jpg")

‘editing image routines, right here
‘…

‘release all Bitmap object resources
myBitmap.Dispose()

[/sourcecode]

The above code it is formally correct, however in same circumstances the .net garbage collector cannot recognize bitmap’s disposing; Dispose() method leaves the image file in an unusable state, then as MSDN said, we MUST release explicitly any reference after a Dispose() call;

with the following code, You will not encounter any problem, and after Dispose() You can edit, move, delete the image file by the filesystem functions…

[sourcecode language=”vb”]
‘create a bitmap object
Dim myBitmap As New Bitmap("c:myimage.jpg")

‘editing image routines, right here
‘…

‘release image reference
While myBitmap IsNot Nothing
myBitmap.Dispose()
myBitmap = Nothing ‘<– tells .net garbage collector to release resources
End While

[/sourcecode]

Happy image editing! 🙂

How to draw a shadow for a bitmap (Drop Shadow Effect in VB.NET / ASP.NET)

Max — Thu, 09 Jan 2020 15:41:16 +0000

I wrote a vb.net subroutine to draw easly a shadow for a Bitmap object; It is possible get a charming shadow in different ways…

Normal black shadow to the bottom right corner
Red shadow to the bottom right corner
Shadow to the bottom left corner
Shadow to the top left corner
Shadow to the top right corner
Shadow with Opacity: “128”
Shadow with Opacity: “128” and Softness: “8”
Shadow with Opacity: “128”, Softness: “8” and Distance: “10”
Shadow without rounded edges

Copy and paste my following vb.net code in your application. it does all the hard job…

[sourcecode language=”vb”]

‘ShadowDirection:
‘ TOP_RIGHT = 1
‘ BOTTOM_RIGHT = 2
‘ BOTTOM_LEFT = 3
‘ TOP_LEFT = 4
‘ShadowOpacity: from 0 to 255
‘ShadowSoftness: from 1 to 30
‘ShadowDistance: from 1 to 50
‘ShadowRoundedEdges: True or False

‘Note:
‘If You set "transparent" as background color, this is replaced with white color.

Public Enum ShadowDirections As Integer
TOP_RIGHT = 1
BOTTOM_RIGHT = 2
BOTTOM_LEFT = 3
TOP_LEFT = 4
End Enum

_
Public Sub DropShadow(ByRef SourceImage As Drawing.Bitmap, _
ByVal ShadowColor As Drawing.Color, _
ByVal BackgroundColor As Drawing.Color, _
Optional ByVal ShadowDirection As ShadowDirections = _
ShadowDirections.BOTTOM_RIGHT, _
Optional ByVal ShadowOpacity As Integer = 190, _
Optional ByVal ShadowSoftness As Integer = 4, _
Optional ByVal ShadowDistance As Integer = 5, _
Optional ByVal ShadowRoundedEdges As Boolean = True)
Dim ImgTarget As Bitmap = Nothing
Dim ImgShadow As Bitmap = Nothing
Dim g As Graphics = Nothing
Try
If SourceImage IsNot Nothing Then
If ShadowOpacity < 0 Then
ShadowOpacity = 0
ElseIf ShadowOpacity > 255 Then
ShadowOpacity = 255
End If
If ShadowSoftness < 1 Then
ShadowSoftness = 1
ElseIf ShadowSoftness > 30 Then
ShadowSoftness = 30
End If
If ShadowDistance < 1 Then
ShadowDistance = 1
ElseIf ShadowDistance > 50 Then
ShadowDistance = 50
End If
If ShadowColor = Color.Transparent Then
ShadowColor = Color.Black
End If
If BackgroundColor = Color.Transparent Then
BackgroundColor = Color.White
End If

‘get shadow
Dim shWidth As Integer = CInt(SourceImage.Width / ShadowSoftness)
Dim shHeight As Integer = CInt(SourceImage.Height / ShadowSoftness)
ImgShadow = New Bitmap(shWidth, shHeight)
g = Graphics.FromImage(ImgShadow)
g.Clear(Color.Transparent)
g.InterpolationMode = InterpolationMode.HighQualityBicubic
g.SmoothingMode = SmoothingMode.AntiAlias
Dim sre As Integer = 0
If ShadowRoundedEdges = True Then sre = 1
g.FillRectangle(New SolidBrush(Color.FromArgb(ShadowOpacity, ShadowColor)), _
sre, sre, shWidth, shHeight)
g.Dispose()

‘draw shadow
Dim d_shWidth As Integer = SourceImage.Width + ShadowDistance
Dim d_shHeight As Integer = SourceImage.Height + ShadowDistance
ImgTarget = New Bitmap(d_shWidth, d_shHeight)
g = Graphics.FromImage(ImgTarget)
g.Clear(BackgroundColor)
g.InterpolationMode = InterpolationMode.HighQualityBicubic
g.SmoothingMode = SmoothingMode.AntiAlias
g.DrawImage(ImgShadow, New Rectangle(0, 0, d_shWidth, d_shHeight), _
0, 0, ImgShadow.Width, ImgShadow.Height, GraphicsUnit.Pixel)
Select Case ShadowDirection
Case ShadowDirections.BOTTOM_RIGHT
g.DrawImage(SourceImage, _
New Rectangle(0, 0, SourceImage.Width,SourceImage.Height), _
0, 0, SourceImage.Width, SourceImage.Height, GraphicsUnit.Pixel)
Case ShadowDirections.BOTTOM_LEFT
g.Dispose()
ImgTarget.RotateFlip(RotateFlipType.RotateNoneFlipX)
g = Graphics.FromImage(ImgTarget)
g.DrawImage(SourceImage, _
New Rectangle(ShadowDistance, 0, SourceImage.Width, SourceImage.Height), _
0, 0, SourceImage.Width, SourceImage.Height, GraphicsUnit.Pixel)
Case ShadowDirections.TOP_LEFT
g.Dispose()
ImgTarget.RotateFlip(RotateFlipType.Rotate180FlipNone)
g = Graphics.FromImage(ImgTarget)
g.DrawImage(SourceImage, _
New Rectangle(ShadowDistance, ShadowDistance, _
SourceImage.Width, SourceImage.Height), _
0, 0, SourceImage.Width, SourceImage.Height, GraphicsUnit.Pixel)
Case ShadowDirections.TOP_RIGHT
g.Dispose()
ImgTarget.RotateFlip(RotateFlipType.RotateNoneFlipY)
g = Graphics.FromImage(ImgTarget)
g.DrawImage(SourceImage, _
New Rectangle(0, ShadowDistance, SourceImage.Width, SourceImage.Height), _
0, 0, SourceImage.Width, SourceImage.Height, GraphicsUnit.Pixel)
End Select

g.Dispose()
g = Nothing
ImgShadow.Dispose()
ImgShadow = Nothing

SourceImage = New Bitmap(ImgTarget)
ImgTarget.Dispose()
ImgTarget = Nothing
End If

Catch ex As Exception
If g IsNot Nothing Then
g.Dispose()
g = Nothing
End If
If ImgShadow IsNot Nothing Then
ImgShadow.Dispose()
ImgShadow = Nothing
End If
If ImgTarget IsNot Nothing Then
ImgTarget.Dispose()
ImgTarget = Nothing
End If
End Try

End Sub
[/sourcecode]

Besides, You can use this sub as in the following example (take a look at the comments…) :

[sourcecode language=”vb”]
Dim file_input As String = "c:myfile.jpg"
Dim file_output As String = "c:myfilewithshadow.jpg"

‘get bitmap…
Dim sourceImage As System.Drawing.Image = System.Drawing.Image.FromFile(file_input)
Dim format As System.Drawing.Imaging.ImageFormat = sourceImage.RawFormat
Dim bmpOut As System.Drawing.Bitmap = New Bitmap(sourceImage)

‘release any reference to the original file…
While sourceImage IsNot Nothing
sourceImage.Dispose()
sourceImage = Nothing
End While

‘drop black shadow on new bitmap with white background…
DropShadow(bmpOut, Color.Black, Color.White)

‘save file…
If bmpOut IsNot Nothing Then
bmpOut.Save(file_output, format)
bmpOut.Dispose()
bmpOut = Nothing
End If
[/sourcecode]

PS:
The subroutine executes only in “STAThread” so it’s thread-safe drawing.

Happy coding…

Max 🙂

How to remove accent marks and german umlauts from URLs and Strings in .NET

Max — Fri, 06 Sep 2019 14:40:50 +0000

I wrote two functions in .NET to remove easly any accent and umlaut marks from a string and to get the equivalent non-accented string, this is very useful to normalize URLs; for example, with the StripAccentMarks() method, from “àbcdèéfghìlmnòpqrstùvzäöüÄÖÜ” u’ll get “abcdeefghilmnopqrstuvzaouAOU”;

besides, if u’ll need to convert each german umlaut to the corresponding two-letter chars, u can also use the ReplaceGermanUmlauts() method…

[sourcecode language=”vb”]
Public Shared Function StripAccentMarks(ByVal input_string As String) As String
Dim n_s As String = input_string.Normalize(NormalizationForm.FormD)
Dim s As New StringBuilder()
Dim c As Char
For i As Integer = 0 To n_s.Length – 1
c = n_s(i)
If System.Globalization.CharUnicodeInfo.GetUnicodeCategory(c) <> System.Globalization.UnicodeCategory.NonSpacingMark Then
s.Append(c)
End If
Next
Return s.ToString
End Function
[/sourcecode]
[sourcecode language=”vb”]
Public Shared Function ReplaceGermanUmlauts(ByVal input_string As String) As String
Dim s As String = input_string
s = s.Replace("ä", "ae")
s = s.Replace("ö", "oe")
s = s.Replace("ü", "ue")
s = s.Replace("Ä", "Ae")
s = s.Replace("Ö", "Oe")
s = s.Replace("Ü", "Ue")
s = s.Replace("ß", "ss")
Return s
End Function
[/sourcecode]

Have a nice day!

Max 😀

Multilingual applications with VB.NET

Max — Fri, 09 Aug 2019 14:36:19 +0000

In this simple tutorial you’ll learn how to manage different languages for a vb.NET application and the simplest way to access programmatically to the string values in the resource compiled files (*.resx) created by Visual Studio;

Adding resource files:

First of all, add a folder named “resources/” in your project.

Inside this folder, right click then from the context menu choose “add an element” -> “new element” -> select “Resource File (resx)” -> create a file named “Resources.en-US.resx”

In the “Resources.en-US.resx” file, You have to write all the strings used by your application.
It’s important that your language resource file is named as “Resources.{Language Code Name}.resx”, so VS can reach automatically this file.

The rsx file is just a list of Key-Value items, then You have to give a key-name for each string value; don’t use spaces in key-names, otherwise it’s best using “_” symbol.

Insert only two test lines in your new rsx file as the following…

KEY – VALUE:
TEST_STRING1 us1 TEST_STRING2 us2

Then, compile your project and if it’s all right, You will find a new folder in “binRelease” named “en-US” created by VS, with a file “{your project name}.resources.dll”; this file contains all the strings for the english-US language (“en-US”) and right now You can access them programmatically.

If You want add a new language to your application, just copy the rsx file and rename it in “Resources.{Language Code Name}.resx” where the language code name is one of those listed at http://msdn.microsoft.com/en-us/library/ee825488(v=cs.20).aspx.

Step 2, how to programmatically select the language and strings:

Add a vb class “Resources.vb” in the “resources” folder with the following code

[sourcecode language=”vb”]
Public Class Resources

Public Shared Function GetValue(ByVal name As ResourceName) As String
Return My.Resources.ResourceManager.GetObject(name.ToString)
End Function

Public Shared Property Language() As CultureCodeName
Get
Dim c As CultureCodeName = Nothing
Dim cs As String = System.Threading.Thread.CurrentThread.CurrentUICulture.ToString().Replace(New Char() {"-"c}, New Char() {"_"c})
For Each cc As CultureCodeName In [Enum].GetValues(GetType(CultureCodeName))
If cs = cc.ToString Then
c = cc
Exit For
End If
Next
Return c
End Get
Set(ByVal cultureCodeName As CultureCodeName)
Dim c As String = cultureCodeName.ToString.Replace(New Char() {"_"c}, New Char() {"-"c})
System.Threading.Thread.CurrentThread.CurrentUICulture = _
System.Globalization.CultureInfo.GetCultureInfo(c)
End Set
End Property

End Class
[/sourcecode]

then, add a vb “code file” named “CultureCodeNames.vb” in “resources” folder with the following code

[sourcecode language=”vb”]

Public Enum CultureCodeName

en_US
‘if You want add a new language, after creating the rsx file,
‘also add here the code name, with "-" replaced in "_"

End Enum

[/sourcecode]

Finally, add the last vb codefile “ResourceNames.vb” in “resources” folder with this code

[sourcecode language=”vb”]

Public Enum ResourceName

‘add here all the key names in the RSX file
TEST_STRING1
TEST_STRING2

End Enum

[/sourcecode]

The configuration is finished.
In your project, add a button to a form, then add the following vb code in the codebehind to learn how to access to different language RSX files and their strings inside.

[sourcecode language=”vb”]

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

‘Select a language for your app
Resources.Language = CultureCodeName.en_US

‘show test string 1
MessageBox.Show(Resources.GetValue(ResourceName.TEST_STRING1))

‘show test string 2
MessageBox.Show(Resources.GetValue(ResourceName.TEST_STRING2))

‘show the current language code
MessageBox.Show(Resources.Language.ToString)

End Sub
[/sourcecode]

It’s very useful because when you will be writing the code, VS automatically suggests the strings that you can use, saving a lot of time and by selecting a language with “Resources.Language”, You can translate your application strings on the fly.

Have a nice day!

Max

How to implement IsNumeric() VB.NET function in C#

Max — Fri, 12 Jul 2019 14:30:42 +0000

This article describes how to implement the useful “IsNumeric” function in Microsoft Visual Basic .NET in Visual C#. The IsNumeric() function returns a Boolean value indicating whether an expression can be evaluated as a number. The IsNumeric() function returns True when the data type of the expression is Short, Integer, Long, Decimal, Single or Double. Returns True if the expression is a string that can be converted to a Double.

Add the following code to your project:

[sourcecode language=”csharp”]
// IsNumeric Function
static bool IsNumeric(object Expression)
{
// Variable to collect the Return value of the TryParse method.
bool isNum;

// Define variable to collect out parameter of the TryParse method. If the conversion fails, the out parameter is zero.
double retNum;

// The TryParse method converts a string in a specified style and culture-specific format to its double-precision floating point number equivalent.
// The TryParse method does not generate an exception if the conversion fails. If the conversion passes, True is returned. If it does not, False is returned.
isNum = Double.TryParse(Convert.ToString(Expression), System.Globalization.NumberStyles.Any, System.Globalization.NumberFormatInfo.InvariantInfo, out retNum );
return isNum;
}
[/sourcecode]

Have a nice day!

Max 🙂

MySqlHelper VB.NET class – easly execute commands against a MySQL database

Max — Wed, 01 Jun 2016 14:28:05 +0000

Hi all, with the following free .net helper class you can easly execute SQL commands against a MySQL database, execute stored procedures, get or programmatically update tables/DataSet objects and convert to and from MySQL datetime types.

Enjoy! 🙂

[sourcecode language=”vb”]

‘ MySqlHelper VB.NET class
‘ http://www.maxvergelli.com/

‘ Vers. 2.1.0
‘ Date: 21/03/2016

‘ Description:
‘ .NET helper class to easly execute SQL commands against a MySQL database,
‘ execute stored procedures, get or programmatically update DataSet objects,
‘ and convert to and from MySQL datetime types.
‘
‘ Before use this class, You have to install and import in your project the
‘ last MySQL Connector/NET at
‘ http://dev.mysql.com/doc/refman/5.0/es/connector-net.html

‘ Permission is hereby granted, free of charge, to any person obtaining a copy
‘ of this software and associated documentation files (the "Software"), to deal
‘ in the Software without restriction, including without limitation the rights
‘ to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
‘ copies of the Software, and to permit persons to whom the Software is
‘ furnished to do so, subject to the following conditions:

‘ The above copyright notice and this permission notice shall be included in
‘ all copies or substantial portions of the Software.

Imports System.Data
Imports System.Globalization
Imports MySql.Data.MySqlClient

Public Class MySqlHelper

Private _cnx_string As String = Nothing
Private _cnx_obj As MySqlConnection = Nothing

Private Function IsConnectionAlive() As Boolean
Dim is_alive As Boolean = False
If _cnx_obj IsNot Nothing AndAlso _cnx_obj.State <> ConnectionState.Closed Then
is_alive = True
End If
Return is_alive
End Function

Private Sub CloseConnection()

Try

If IsConnectionAlive() Then
_cnx_obj.Close()
End If
_cnx_obj = Nothing

Catch ex As Exception

_cnx_obj = Nothing

End Try

End Sub

Public ReadOnly Property ConnectionString() As String
Get
Return _cnx_string
End Get
End Property

Public Function IsOpen() As Boolean
Return IsConnectionAlive()
End Function

Public Sub New(Optional ByVal db_connection_string As String = "", _
Optional ByVal open_connection As Boolean = False)

_cnx_string = db_connection_string

If _cnx_string.Length > 0 And open_connection = True Then

Dim is_open As Boolean = Open(_cnx_string)

End If

End Sub

Public Function Open(ByVal db_connection_string As String) As Boolean

Dim success As Boolean = False
Try

If IsConnectionAlive() = False Then

If db_connection_string.Length > 0 AndAlso _cnx_obj Is Nothing Then

_cnx_string = db_connection_string
_cnx_obj = New MySqlConnection
_cnx_obj.ConnectionString = _cnx_string
_cnx_obj.Open()
success = True

End If

Catch ex As Exception

CloseConnection()
success = False

End Try
Return success

End Function

Public Sub Close()

CloseConnection()

End Sub

Protected Overrides Sub Finalize()
CloseConnection()
End Sub

‘get a DataRow object with the first row of a SQL select command
Public Function SelectFirstRow(ByVal sql_select As String) As DataRow

Dim ds As DataSet = SelectRows(sql_select)
If ds Is Nothing Then
Return Nothing
End If
If ds.Tables.Count < 1 Then
Return Nothing
End If
If ds.Tables(0).Rows.Count < 1 Then
Return Nothing
End If
Return ds.Tables(0).Rows(0)

End Function

‘get a DataSet object with the rows of a SQL select command
Public Function SelectRows(ByVal sql_select As String) As DataSet

Dim ds As DataSet = Nothing
Try

If IsConnectionAlive() Then

Dim cmd As MySqlCommand = New MySqlCommand(sql_select, _cnx_obj)

Dim da As MySqlDataAdapter = New MySqlDataAdapter
da.SelectCommand = cmd

ds = New DataSet
da.Fill(ds)

da = Nothing

End If

Catch ex As Exception

ds = Nothing

End Try
Return ds

End Function

‘Execute a MySql Stored Procedure
Public Overloads Function ExecuteStoredProcedure(ByVal stored_procedure_name As String) As DataSet

Return ExecuteProcedure(stored_procedure_name)

End Function

‘Execute a MySql Stored Procedure with parameters

‘How to create the parameters
‘Dim param As MySqlParameter = New MySqlParameter("?v_id", MySqlDbType.Int32)
‘param.Value = 1
‘param.Direction = ParameterDirection.Input

Public Overloads Function ExecuteStoredProcedure(ByVal stored_procedure_name As String, _
ByVal ParamArray parameters As MySqlParameter()) As DataSet

Return ExecuteProcedure(stored_procedure_name, parameters)

End Function

Private Function ExecuteProcedure(ByVal procedure_name As String, _
ByVal ParamArray sql_parameters As MySqlParameter()) As DataSet

Dim ds As DataSet = Nothing
Try
If IsConnectionAlive() Then

Dim cmd As New MySqlCommand(procedure_name, _cnx_obj)

cmd.CommandType = CommandType.StoredProcedure

If sql_parameters IsNot Nothing Then
For Each p As MySqlParameter In sql_parameters
cmd.Parameters.Add(p)
Next
End If

Dim da As MySqlDataAdapter = New MySqlDataAdapter
da.SelectCommand = cmd
ds = New DataSet
da.Fill(ds)
da = Nothing

cmd.Parameters.Clear()

End If
Catch ex As Exception

ds = Nothing

End Try

Return ds

End Function

‘UpdateRows() function automatically generates single-table commands used to reconcile changes made to a DataSet
‘with the associated table in the MySQL database.
‘The function gets
‘ – the SQL SELECT used to populate the dataset
‘ – the updated dataset
‘ – the table name that must be updated in the database
‘Note:
‘The SQL SELECT must also return at least one primary key or unique column, otherwise an exception is generated;

Public Function UpdateRows(ByVal sql_select As String, ByRef input_dataset As DataSet, ByVal table_name As String) As Boolean

Dim success As Boolean = False
Try

If IsConnectionAlive() Then

Dim data_adapter As New MySqlDataAdapter(sql_select, _cnx_obj)
Dim cmd_builder As New MySqlCommandBuilder(data_adapter)
data_adapter.Update(input_dataset, table_name)
success = True

End If

Catch ex As Exception

success = False

End Try

Return success

End Function

‘To use a MySqlDataReader,
‘You have to use OpenReader() and CloseReader() functions like in the following example:
‘
‘ Public Sub ReadMyData(ByVal connection_string As String)
‘
‘ Dim mysql As MySqlHelper = New MySqlHelper()
‘ mysql.Open(connection_string)
‘
‘ Dim sql As String = "SELECT OrderID, CustomerID FROM Orders"
‘ Dim reader As MySqlDataReader = Nothing
‘
‘ mysql.OpenReader(reader, sql)
‘ While reader.Read()
‘ Console.WriteLine((reader.GetInt32(0) & ", " & reader.GetString(1)))
‘ End While
‘ mysql.CloseReader(reader)
‘
‘ mysql.Close()
‘
‘ End Sub

Public Sub OpenReader(ByRef reader As MySqlDataReader, ByVal sql_select As String)

Try
If IsConnectionAlive() Then

Dim cmd As New MySqlCommand(sql_select, _cnx_obj)
reader = cmd.ExecuteReader()

End If

Catch ex As Exception

reader = Nothing

End Try

End Sub

Public Sub CloseReader(ByRef reader As MySqlDataReader)

Try

reader.Close()

Catch ex As Exception

End Try

End Sub

‘Execute SQL command and return the number of records affected
Public Function Execute(ByVal sql_command As String) As Long

Dim affected_rows As Long = 0

Try
If IsConnectionAlive() Then

Dim cmd As New MySqlCommand(sql_command, _cnx_obj)

affected_rows = cmd.ExecuteNonQuery()

End If

Catch ex As Exception

affected_rows = 0

End Try

Return affected_rows

End Function

‘GetSingleValue() function executes the query, and returns the value of the first column of the first row in the
‘result set returned by the query. Extra columns or rows are ignored.
‘Note:
‘Use the GetSingleValue() method to retrieve a single value (for example, an aggregate value)
‘from a database, like "select count(*) from region"

Public Overloads Function GetSingleValue(ByVal sql_select As String) As Object

Return ExecuteScalar(sql_select, DirectCast(Nothing, MySqlParameter()))

End Function

Public Overloads Function GetSingleValue(ByVal sql_select As String, ByVal ParamArray sql_parameters As MySqlParameter()) As Object

Return ExecuteScalar(sql_select, sql_parameters)

End Function

‘ExecuteScalar: Executes the query, and returns the value (integer/string) of the first column of the first row in the result set returned by the query. Extra columns or rows are ignored.
Private Function ExecuteScalar(ByVal sql_select As String, ByVal ParamArray sql_parameters As MySqlParameter()) As Object

Dim row As Object = Nothing
Try
If IsConnectionAlive() Then

Dim cmd As New MySqlCommand(sql_select, _cnx_obj)
If sql_parameters IsNot Nothing Then
For Each p As MySqlParameter In sql_parameters
cmd.Parameters.Add(p)
Next
End If
row = cmd.ExecuteScalar()
cmd.Parameters.Clear()

End If
Catch ex As Exception

row = Nothing

End Try

Return row

End Function

’25/1/12 -> 2012-01-25
Public Overloads Function ConvertToMySqlDate(ByVal input_date As Date) As String

Return input_date.ToString("yyyy-MM-dd")

End Function

’25/1/12 -> 2012-01-25
Public Overloads Function ConvertToMySqlDate(ByVal input_date As String) As String

Return ConvertDateTime(input_date, DATETIME_TYPE.MYSQL, True)

End Function

’25/1/12 13:00 -> 2012-01-25 13:00:00
Public Overloads Function ConvertToMySqlDateTime(ByVal input_datetime As DateTime) As String

Return input_datetime.ToString("yyyy-MM-dd HH:mm:ss")

End Function

’25/1/12 13:00 -> 2012-01-25 13:00:00
Public Overloads Function ConvertToMySqlDateTime(ByVal input_datetime As String) As String

Return ConvertDateTime(input_datetime, DATETIME_TYPE.MYSQL)

End Function

‘2012-01-25 -> 25-01-2012
Public Overloads Function ConvertToDate(ByVal mysql_date As Date) As String

Return mysql_date.ToString("dd-MM-yyyy")

End Function

‘2012-01-25 -> 25-01-2012
Public Overloads Function ConvertToDate(ByVal mysql_date As String) As String

Return ConvertDateTime(mysql_date, DATETIME_TYPE.SYSTEM, True)

End Function

‘2012-01-25 13:00:00 -> 25-01-2012 13:00:00
Public Overloads Function ConvertToDateTime(ByVal mysql_datetime As DateTime) As String

Return mysql_datetime.ToString("dd-MM-yyyy HH:mm:ss")

End Function

‘2012-01-25 13:00:00 -> 25-01-2012 13:00:00
Public Overloads Function ConvertToDateTime(ByVal mysql_datetime As String) As String

Return ConvertDateTime(mysql_datetime, DATETIME_TYPE.SYSTEM)

End Function

Private Enum DATETIME_TYPE As Integer
SYSTEM = 0
MYSQL = 1
End Enum

Private Function ConvertDateTime(ByVal input_datetime As String, ByVal output_datetime_type As DATETIME_TYPE, _
Optional ByVal get_only_date As Boolean = False) As String

‘The function returns a datetime in a well-formatted string for regular or MySQL use.
‘You have to insert a datetime string formatted by {,/,-,.,:} symbols.
‘Besides, for the input date, You need to specify "day, month and year";
‘for the time, only "hour and minutes", "seconds" doesn’t matter.

‘The function returns Nothing if an error is encountered.

‘You can select one of the following datetime types as output:
‘SYSTEM: "(2 digits day)-(2 digits month)-(4 digits year) hours:minutes:seconds"
‘MYSQL: "(4 digits year)-(2 digits month)-(2 digits day) hours:minutes:seconds"

‘examples:
‘for a regular datetime in input and
‘a MySql datetime as output, You ‘ll get…

’25-1-08 -> 2008-01-25 00:00:00
’25/1/08 -> 2008-01-25 00:00:00
’25/1/08 12:00 -> 2008-01-25 12:00:00
’25-1-08 12:00 -> 2008-01-25 12:00:00
‘25.1.08 12:00 -> 2008-01-25 12:00:00
‘25.1.08 12.00 -> 2008-01-25 12:00:00
‘25.1.08 12.00.23 -> 2008-01-25 12:00:23

Dim dt_out As String = Nothing
Dim dt_type As String = ""
If output_datetime_type = DATETIME_TYPE.MYSQL Then
dt_type = "yyyy-MM-dd HH’:’mm’:’ss"
Else
dt_type = "dd-MM-yyyy HH’:’mm’:’ss"
End If
Try
If input_datetime.IndexOf(".", 0, CompareMethod.Binary) > 0 Then
Dim tmp() As String = input_datetime.Split(" ")
If tmp.GetUpperBound(0) > 0 Then
input_datetime = tmp(0).Replace(".", "-") & " " & tmp(1).Replace(".", ":")
End If
End If
Dim myDTFI As DateTimeFormatInfo = New CultureInfo("it-IT", False).DateTimeFormat
myDTFI.FullDateTimePattern = "dd-MM-yyyy HH’:’mm’:’ss"
myDTFI.DateSeparator = "-"
myDTFI.TimeSeparator = ":"
Dim myDT As New DateTime
myDT = System.Convert.ToDateTime(input_datetime, myDTFI)
dt_out = Format(myDT, dt_type)
myDT = Nothing
myDTFI = Nothing
If get_only_date = True Then
Dim s() As String = dt_out.Split(" ")
If s.GetUpperBound(0) > 0 Then
dt_out = s(0)
End If
End If
Catch ex As Exception
dt_out = Nothing
End Try
Return dt_out

End Function

End Class

[/sourcecode]

How to extract text content from tags in VB.Net

Max — Fri, 27 May 2016 14:56:42 +0000

With this simple vb.net function You are able to extract content from HTML tags, useful and smart

Max 🙂

[sourcecode language=”vb”]
Public Function GetTagContent(ByRef html As String, ByVal start_tag As String, ByVal end_tag As String) As String
Dim s As String = ""
Dim content() As String = html.Split(start_tag)
If content.Count > 1 Then
Dim parts() As String = content(1).Split(end_tag)
If parts.Count > 1 Then
s = parts(0)
End If
End If
Return s
End Function
[/sourcecode]

Updated version of CryptographyHelper class for .NET Framework 4

Max — Fri, 27 May 2016 14:53:01 +0000

This updated version of mine “CryptographyHelper” wrapper/helper class supports .NET Framework 4 .

With this vb.net class you can easly encrypt/decrypt strings using a robust symmetric Rijndael algorithm or you can get also MD5 or SHA1, SHA256 hash codes of a string.

During the encryption, the CryptographyHelper encrypts a clear text and saves it in a binary stream, then converts the binary output in Hexadecimal or Base64 encoding type for a string rapresentation. The opposite job during the decryption.

How to use:

[sourcecode language=”vb”]
Imports {project’s name}.Cryptography

Dim crypt As New CryptographyHelper

‘select your favorite encoding type (Hexadecimal or Base64) for encrypted/decryptet text
‘in output/input;
‘during the encryption, the CryptographyHelper encrypts a clear text and saves it in a
‘binary stream, then converts the binary output in Hexadecimal or Base64 encoding type
‘for a string rapresentation. The opposite job during the decryption.
crypt.EncodingType = CryptographyHelper.ENCODING_TYPE.Hexadecimal

‘choose a password
Dim password As String = "my secret password"

‘encrypt/decrypt strings using a robust symmetric Rijndael algorithm
Dim encrypted_text As String = crypt.Encrypt("plain text to encrypt…", password)
Dim decrypted_text As String = crypt.Decrypt(encrypted_text, password)

‘you can also get an hash of a string
Dim MD5hash As String = crypt.GetHash("string to hash", CryptographyHelper.HASH_TYPE.MD5)
Dim SHA1hash As String = crypt.GetHash("string to hash", CryptographyHelper.HASH_TYPE.SHA1)
Dim SHA256hash As String = crypt.GetHash("string to hash", CryptographyHelper.HASH_TYPE.SHA256)
[/sourcecode]

Enjoy 🙂

Max

[sourcecode language=”vb”]

‘ CryptographyHelper & Cryptography VB.NET classes for .NET Framework 4
‘ http://www.maxvergelli.com/
‘
‘ Copyright (c) 2016 Max Vergelli
‘
‘ Vers. 3.5.1
‘ Date: 23/03/2016
‘
‘ Description:
‘ With the “CryptographyHelper” wrapper class, you can easly encrypt/decrypt strings in
‘ .NET Framework 4 using a robust symmetric Rijndael algorithm or you can get also MD5
‘ or SHA1, SHA256 hash codes of a string.
‘ During the encryption, the CryptographyHelper encrypts a clear text and saves it in a
‘ binary stream, then converts the binary output in Hexadecimal or Base64 encoding type
‘ for a string rapresentation. The opposite job during the decryption.
‘
‘
‘ Usage:
‘
‘ Imports {project’s name}.Cryptography
‘
‘ Dim crypt As New CryptographyHelper
‘
‘ ‘select your favorite encoding type (Hexadecimal or Base64) for encrypted/decryptet text
‘ ‘in output/input;
‘ ‘during the encryption, the CryptographyHelper encrypts a clear text and saves it in a
‘ ‘binary stream, then converts the binary output in Hexadecimal or Base64 encoding type
‘ ‘for a string rapresentation. The opposite job during the decryption.
‘ crypt.EncodingType = CryptographyHelper.ENCODING_TYPE.Hexadecimal
‘
‘ ‘choose a password
‘ Dim password As String = "my secret password"
‘
‘ encrypt/decrypt strings using a robust symmetric Rijndael algorithm
‘ Dim encrypted_text As String = crypt.Encrypt("plain text to encrypt…", password)
‘ Dim decrypted_text As String = crypt.Decrypt(encrypted_text, password)
‘
‘ ‘you can also get an hash of a string
‘ Dim MD5hash As String = crypt.GetHash("string to hash", CryptographyHelper.HASH_TYPE.MD5)
‘ Dim SHA1hash As String = crypt.GetHash("string to hash", CryptographyHelper.HASH_TYPE.SHA1)
‘ Dim SHA256hash As String = crypt.GetHash("string to hash", CryptographyHelper.HASH_TYPE.SHA256)
‘
‘
‘ License:
‘
‘ Permission is hereby granted, free of charge, to any person obtaining a copy
‘ of this software and associated documentation files (the "Software"), to deal
‘ in the Software without restriction, including without limitation the rights
‘ to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
‘ copies of the Software, and to permit persons to whom the Software is
‘ furnished to do so, subject to the following conditions:
‘
‘ The above copyright notice and this permission notice shall be included in
‘ all copies or substantial portions of the Software.
‘
‘ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
‘ IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
‘ FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
‘ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
‘ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
‘ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
‘ THE SOFTWARE.

Imports System
Imports System.IO
Imports System.Text
Imports System.Security.Cryptography

Namespace Cryptography

Public Class CryptographyHelper

Private _encoding As ENCODING_TYPE

Public Enum ENCODING_TYPE As Integer
Hexadecimal = 1
Base64 = 2
End Enum

Public Enum HASH_TYPE As Integer
MD5 = 1
SHA1 = 2
SHA256 = 3
SHA512 = 4
End Enum

Public Sub New(Optional ByVal encoding As ENCODING_TYPE = ENCODING_TYPE.Hexadecimal)

‘by default encryption/hashing outputs hexadecimal strings
‘and decryption get hexstrings as input
If encoding <> ENCODING_TYPE.Hexadecimal And encoding <> ENCODING_TYPE.Base64 Then
encoding = ENCODING_TYPE.Hexadecimal
End If
_encoding = encoding

End Sub

Public Property EncodingType() As ENCODING_TYPE
Get
Return _encoding
End Get
Set(ByVal value As ENCODING_TYPE)
_encoding = value
End Set
End Property

Public Function GetHash(ByRef input As String, Optional ByVal type As HASH_TYPE = HASH_TYPE.MD5) As String

Dim crypt As New Cryptography
Dim bytes() As Byte = Nothing
Select Case type
Case HASH_TYPE.MD5
bytes = crypt.CreateMD5Hash(input)
Case HASH_TYPE.SHA1
bytes = crypt.CreateSHA1Hash(input)
Case HASH_TYPE.SHA256
bytes = crypt.CreateSHA256Hash(input)
Case HASH_TYPE.SHA512
bytes = crypt.CreateSHA512Hash(input)
Case Else
bytes = crypt.CreateMD5Hash(input)
End Select
Dim hash As String = ""
Select Case _encoding
Case ENCODING_TYPE.Hexadecimal
hash = crypt.BytesToHexString(bytes)
Case ENCODING_TYPE.Base64
hash = crypt.BytesToBase64(bytes)
Case Else
hash = crypt.BytesToHexString(bytes)
End Select
crypt = Nothing
Return hash

End Function

Public Function Encrypt(ByRef input As String, ByRef password As String) As String

Dim crypt As New Cryptography(password)
Dim bytes() As Byte = crypt.Encrypt(input)
Dim encrypted As String = ""
If bytes IsNot Nothing Then
Select Case _encoding
Case ENCODING_TYPE.Hexadecimal
encrypted = crypt.BytesToHexString(bytes)
Case ENCODING_TYPE.Base64
encrypted = crypt.BytesToBase64(bytes)
Case Else
encrypted = crypt.BytesToHexString(bytes)
End Select
End If
crypt = Nothing
Return encrypted

End Function

Public Function Decrypt(ByRef input As String, ByRef password As String) As String

Dim decrypted As String = ""
If input.Length > 0 Then
Dim crypt As New Cryptography(password)
Dim enc_bytes() As Byte = Nothing
Select Case _encoding
Case ENCODING_TYPE.Hexadecimal
enc_bytes = crypt.HexStringToBytes(input)
Case ENCODING_TYPE.Base64
enc_bytes = crypt.Base64ToBytes(input)
Case Else
enc_bytes = crypt.HexStringToBytes(input)
End Select
decrypted = crypt.Decrypt(enc_bytes)
crypt = Nothing
End If
Return decrypted

End Function

End Class

Public Class Cryptography

Private _key_str As String = Nothing
Private _key_byte() As Byte = Nothing
Private _txt_converter As New UnicodeEncoding
Private _rijndael As New RijndaelManaged ‘"rèin-daal" 🙂

Public Sub New(Optional ByVal encryption_key As String = "")

If encryption_key <> "" Then EncryptionKey = encryption_key

End Sub

Protected Overrides Sub Finalize()

If _txt_converter IsNot Nothing Then
_txt_converter = Nothing
End If
If _rijndael IsNot Nothing Then
_rijndael = Nothing
End If
_key_str = Nothing
_key_byte = Nothing

End Sub

Public Property EncryptionKey() As String

Get
Return _key_str
End Get

Set(ByVal value As String)

Try
‘set the key string
_key_str = value

‘set hash in bytes of the key string
Dim hash256 As New SHA256Managed
_key_byte = hash256.ComputeHash(_txt_converter.GetBytes(_key_str))
hash256 = Nothing

‘If UBound(_key_byte) < 0 Then Exit Property ‘.NET <= 3.5
If _key_byte.GetUpperBound(0) < 0 Then Exit Property ‘.NET Framework 4

‘set Rijndael Key and IV vector for 256 bit encryption
Dim main_key(31) As Byte
Dim main_vector(15) As Byte
Dim diff_block As Integer = 5
_rijndael.KeySize = 256 ‘bit

Dim n As Integer = 0
Dim x As Integer = 0
Dim y As Integer = 0

‘For n = 0 To UBound(main_key) ‘.NET <= 3.5
For n = 0 To main_key.GetUpperBound(0) ‘.NET Framework 4

main_key(n) = _key_byte(x)
‘If n > diff_block And n <= UBound(main_vector) + diff_block Then ‘.NET <= 3.5
If n > diff_block And n <= main_vector.GetUpperBound(0) + diff_block Then ‘.NET Framework 4
main_vector(y) = _key_byte(x)
y = y + 1
End If
x = x + 1

‘If x > UBound(_key_byte) Then x = 0 ‘.NET <= 3.5
If x > _key_byte.GetUpperBound(0) Then x = 0 ‘.NET Framework 4

Next
_rijndael.Key = main_key
_rijndael.IV = main_vector

Catch

‘set a blank encryption key then we cannot encrypt/decrypt
_key_str = Nothing

End Try

End Set

End Property

Public Function Encrypt(ByRef clear_text As String) As Byte()

Dim enc_bytes() As Byte = Nothing
Try
If _key_str IsNot Nothing Then
‘get byte array from text
Dim bytes() As Byte = _txt_converter.GetBytes(clear_text)

‘encrypt data
Dim encryptor As ICryptoTransform = _rijndael.CreateEncryptor()
Dim msEncrypt As New MemoryStream
Dim csEncrypt As New CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write)

‘write all data to the crypto stream and flush it
csEncrypt.Write(bytes, 0, bytes.Length)
csEncrypt.FlushFinalBlock()

‘get encrypted byte array
enc_bytes = msEncrypt.ToArray()

msEncrypt = Nothing
csEncrypt = Nothing
End If
Catch

End Try

Return enc_bytes

End Function

Public Function Decrypt(ByRef encrypted_text() As Byte) As String

Dim dec_text As String = Nothing

Try
If _key_str IsNot Nothing Then
Dim decryptor As ICryptoTransform = _rijndael.CreateDecryptor()
Dim msDecrypt As New MemoryStream(encrypted_text)
Dim csDecrypt As New CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read)

‘prepare buffer
Dim bytes() As Byte = New Byte(encrypted_text.Length – 1) {}

‘read the data out of the crypto stream
csDecrypt.Read(bytes, 0, bytes.Length)

‘convert the byte array back into a string
dec_text = _txt_converter.GetString(bytes)

‘strip null chars at the end of the string
StripNullAtEnd(dec_text)

msDecrypt = Nothing
csDecrypt = Nothing
End If
Catch

End Try

Return dec_text

End Function

Public Function BytesToBase64(ByRef input_bytes() As Byte) As String

Dim s As String = Nothing
Try
s = Convert.ToBase64String(input_bytes)
Catch

End Try
Return s

End Function

Public Function Base64ToBytes(ByRef input_base64 As String) As Byte()

Dim b() As Byte = Nothing
Try
b = Convert.FromBase64String(input_base64)
Catch

End Try
Return b

End Function

Public Function BytesToHexString(ByRef input_bytes() As Byte) As String

Dim s As String = Nothing
Try
‘Dim s As String = BitConverter.ToString(input_bytes).Replace("-", String.Empty)
Dim builder As New StringBuilder()
For i As Integer = 0 To input_bytes.Length – 1
builder.AppendFormat("{0:x2}", input_bytes(i))
Next
s = builder.ToString()
builder = Nothing
Catch

End Try
Return s

End Function

Public Function HexStringToBytes(ByRef input_hex_string As String) As Byte()

Dim bytes As Byte() = Nothing
Try
‘i variable used to hold position in string
Dim i As Integer = 0
‘x variable used to hold byte array element position
Dim x As Integer = 0
‘allocate byte array based on half of string length
bytes = New Byte((input_hex_string.Length) 2 – 1) {}
‘loop through the string – 2 bytes at a time converting
‘it to decimal equivalent and store in byte array
While input_hex_string.Length > i + 1
Dim lngDecimal As Long = Convert.ToInt32(input_hex_string.Substring(i, 2), 16)
bytes(x) = Convert.ToByte(lngDecimal)
i = i + 2
x += 1
End While
‘return the finished byte array of decimal values
Catch

End Try
Return bytes

End Function

Public Function CreateMD5Hash(ByRef input As String) As Byte()

Dim hash As Byte() = Nothing
Try
Dim bytes() As Byte = _txt_converter.GetBytes(input)
Dim objMD5 As New MD5CryptoServiceProvider
hash = objMD5.ComputeHash(bytes)
objMD5 = Nothing
Catch

End Try
Return hash

End Function

Public Function CreateSHA1Hash(ByRef input As String) As Byte()

Dim hash As Byte() = Nothing
Try
Dim bytes() As Byte = _txt_converter.GetBytes(input)
Dim objSHA As New SHA1CryptoServiceProvider
hash = objSHA.ComputeHash(bytes)
objSHA = Nothing
Catch

End Try
Return hash

End Function

Public Function CreateSHA256Hash(ByRef input As String) As Byte()
Dim hash As Byte() = Nothing
Try
Dim bytes() As Byte = _txt_converter.GetBytes(input)
Dim objSHA As New SHA256CryptoServiceProvider
hash = objSHA.ComputeHash(bytes)
objSHA = Nothing
Catch

End Try
Return hash

End Function

Public Function CreateSHA512Hash(ByRef input As String) As Byte()
Dim hash As Byte() = Nothing
Try
Dim bytes() As Byte = _txt_converter.GetBytes(input)
Dim objSHA As New SHA512CryptoServiceProvider
hash = objSHA.ComputeHash(bytes)
objSHA = Nothing
Catch

End Try
Return hash

End Function

Private Sub StripNullAtEnd(ByRef input_string As String)

Dim nullchar As Char = Convert.ToChar(0) ‘&H0
If input_string.Length > 0 And input_string.EndsWith(nullchar.ToString) Then
Dim n As Long
For n = input_string.Length – 1 To 0 Step -1
If input_string.Chars(n) <> nullchar Then
input_string = input_string.Substring(0, n + 1)
Exit For
End If
Next
End If
Convert.ToString(input_string)

End Sub

End Class

End Namespace

[/sourcecode]

Useful extension methods for the String .Net class and string manipulation, with support of IntelliSense

Max — Fri, 27 May 2016 14:33:08 +0000

Hi to all, I wrote this .NET module that extends String class with useful methods to modify alphanumeric characters and symbols. It fully integrates with the compiler so You are able to recognize extension methods by IntelliSense; in the bottom of the article, see the module’s code.

This is an example of what you can do:

[sourcecode language=”vb”]
‘remove accent marks (ex. "à" to "a")
Dim accents As String = "àèìòù"
accents = accents.StripAccentMarks()

‘remove tags (ex. "test" to "test")
Dim tags As String = "test"
tags = tags.StripTags()

‘remove symbols from the string but leave "," and ";" then trim the spaces
Dim s As String = " hi, this is a test; 5 is a number! – up-to-date example. "
Dim symbols_exceptions() As Char = {",", ";"}
Dim new_string As String = s.StripNonAlphanumeric(Nothing, symbols_exceptions).TrimSpaces

‘remove punctuation but not hyphens in words
Dim h As String = "punctuation and hyphens, as ‘-‘, will be deleted but not hyphens in words like ‘up-to-date’."
Dim filtered As String = h.StripPunctuation(True)

‘padding strings…
Dim mystring1 As String = "max"
Dim mystring2 As String = "vergelli"
Console.WriteLine(mystring1.Pad(10, ".") & vbCrLf & mystring2.Pad(10, "."))
‘it will print
‘ "…….max"
‘ "..vergelli"

‘padding integers…
Dim mynumber1 As Integer = 10
Dim mynumber2 As Integer = 1000
Console.WriteLine(mynumber1.Pad(10, "0") & vbCrLf & mynumber2.Pad(10, "0"))
‘it will print
‘ "0000000010"
‘ "0000001000"

‘get the first 3 characters of the string
Dim ls As String = s.Left(3)

‘get the last 3 characters of the string
Dim rs As String = s.Right(3)

‘get characters in the middle of the string
Dim ms As String = s.Mid(5, 3)

‘get only the symbols
Dim symbols As String = s.StripAlphanumeric()

‘leave only one space between words but it does not trim spaces at start and at end of the string
symbols = symbols.TrimSpaces(True, True)

‘get only the numbers
Dim numbers As String = s.StripNonNumeric()

Dim n As String = "5"
If n.IsNumeric Then Console.WriteLine("’n’ variable contains a numeric value.")

‘convert a string to an integer…
n = n.ToInteger()
[/sourcecode]

How to install the module:

all that is required to be able to run these extension methods is that they be in scope, therefore You have to import this module in your classes with the header “Imports [Project’s name].Extensions”, so all methods will be visible also in IntelliSense.

Notes:

All the methods do not change the value of the current instance, instead, they return always a new string.
Only an instance of String can use the these methods, any other class trying to use the string extension methods will throw a compilation error.
If an extension method is called for an object that is set to Nothing, the extension method executes. This does not apply to ordinary instance methods. You can explicitly check for Nothing in the extension method.
Notice that when the extension methods are invoked, You have to omit the first parameter; Why no argument is sent in for the first parameter? The first parameter in the method definitions is only bound to caller object (the instance of String that calls them), so the compiler will treat the argument in the first parameter (named “instance_handler”) as the caller object.

Finally, the source code of the module, enjoy!… 🙂

[sourcecode language=”vb”]
‘ StringExtensions VB.NET module
‘ http://www.maxvergelli.com/

‘ Vers. 3.0.0
‘ Date: 22/03/2016

‘   Description:
‘   .NET module that extends String class with useful methods to modify
‘   alphanumeric characters and symbols. It fully integrates with the compiler
‘   so You are able to recognize extension methods by IntelliSense.
‘
‘
‘   License:
‘
‘   Permission is hereby granted, free of charge, to any person obtaining a copy
‘   of this software and associated documentation files (the "Software"), to deal
‘   in the Software without restriction, including without limitation the rights
‘   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
‘   copies of the Software, and to permit persons to whom the Software is
‘   furnished to do so, subject to the following conditions:

‘ The above copyright notice and this permission notice shall be included in
‘ all copies or substantial portions of the Software.

‘   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
‘   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
‘   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
‘   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
‘   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
‘   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
‘   THE SOFTWARE.
‘
‘
‘   Installation:
‘
‘   All that is required to be able to run these extension methods is that they be in scope, therefore
‘   You have to import this module in your classes with the header "Imports [Project’s name].Extensions",
‘   so all methods will be visible also in IntelliSense.
‘
‘
‘   Notes:
‘
‘   1) All the methods do not change the value of the current instance, instead, they return always a new string.

‘   2) Only an instance of String can use the these methods, any other class trying to use the string extension
‘      methods will throw a compilation error.
‘
‘   3) If an extension method is called for an object that is set to Nothing, the extension method executes. This
‘      does not apply to ordinary instance methods. You can explicitly check for Nothing in the extension method.
‘
‘   4) Notice that when the extension methods are invoked, You have to omit the first parameter;
‘      Why no argument is sent in for the first parameter?
‘      The first parameter in the method definitions is only bound to caller object (the instance of String that
‘      calls them), so the compiler will treat the argument in the first parameter (named "instance_handler") as
‘      the caller object.
‘
‘
‘   Usage:
‘
‘   Imports {Your project’s name}.Extensions
‘
‘   Public Class Test
‘       Public Sub TestExtensions()
‘
‘        ‘remove accent marks (ex. "à" to "a")
‘        Dim accents As String = "àèìòù"
‘        accents = accents.StripAccentMarks()
‘
‘        ‘remove tags (ex. "test" to "test")
‘        Dim tags As String = "test"
‘        tags = tags.StripTags()
‘
‘        ‘remove symbols from the string but leave "," and ";" then trim the spaces
‘        Dim s As String = " hi, this   is a test;   5 is a number! – up-to-date example.   "
‘        Dim symbols_exceptions() As Char = {",", ";"}
‘        Dim new_string As String = s.StripNonAlphanumeric(Nothing, symbols_exceptions).TrimSpaces
‘
‘        ‘remove punctuation but not hyphens in words
‘        Dim h As String = "punctuation and hyphens, as ‘-‘, will be deleted but not hyphens in words like ‘up-to-date’."
‘        Dim filtered As String = h.StripPunctuation(True)
‘
‘        ‘padding strings…
‘        Dim mystring1 As String = "max"
‘        Dim mystring2 As String = "vergelli"
‘        Console.WriteLine(mystring1.Pad(10, ".") & vbCrLf & mystring2.Pad(10, "."))
‘        ‘it will print
‘        ‘   "…….max"
‘        ‘   "..vergelli"
‘
‘        ‘padding integers…
‘        Dim mynumber1 As Integer = 10
‘        Dim mynumber2 As Integer = 1000
‘        Console.WriteLine(mynumber1.Pad(10, "0") & vbCrLf & mynumber2.Pad(10, "0"))
‘        ‘it will print
‘        ‘   "0000000010"
‘        ‘   "0000001000"
‘
‘        ‘get the first 3 characters of the string
‘        Dim ls As String = s.Left(3)
‘
‘        ‘get the last 3 characters of the string
‘        Dim rs As String = s.Right(3)
‘
‘        ‘get characters in the middle of the string
‘        Dim ms As String = s.Mid(5, 3)
‘
‘        ‘get only the symbols
‘        Dim symbols As String = s.StripAlphanumeric()
‘
‘        ‘leave only one space between words but it does not trim spaces at start and at end of the string
‘        symbols = symbols.TrimSpaces(True, True)
‘
‘        ‘get only the numbers
‘        Dim numbers As String = s.StripNonNumeric()
‘
‘        Dim n As String = "5"
‘        If n.IsNumeric Then Console.WriteLine("’n’ variable contains a numeric value.")
‘
‘        ‘convert a string to an integer…
‘        n = n.ToInteger()
‘
‘       End Sub
‘   End Class

Imports System.Runtime.CompilerServices
Imports System.Text
Imports System.Text.RegularExpressions
Imports System.Web

Namespace Extensions

Module StringExtensions

_
Public Function IsNumeric(ByRef instance_handler As Object) As Boolean
Dim is_numeric As Boolean = False
‘Define variable to collect out parameter of the TryParse method.
‘If the conversion fails, the out parameter is zero.
Dim tmp As Double
‘The TryParse method converts a string in a specified style and culture-specific format to its
‘double-precision floating point number equivalent.
‘The TryParse method does not generate an exception if the conversion fails. If the conversion passes,
‘True is returned. If it does not, False is returned.
is_numeric = [Double].TryParse(Convert.ToString(instance_handler), System.Globalization.NumberStyles.Any, System.Globalization.NumberFormatInfo.InvariantInfo, tmp)
Return is_numeric
End Function

_
Public Function ToInteger(ByRef instance_handler As String) As Integer
Return Integer.Parse(instance_handler)
End Function

_
Public Function Left(ByRef instance_handler As String, length As Integer) As String
Return instance_handler.Substring(0, length)
End Function

_
Public Function Right(ByRef instance_handler As String, length As Integer) As String
Return instance_handler.Substring(instance_handler.Length – length, length)
End Function

_
Public Function Mid(ByRef instance_handler As String, start_index As Integer, length As Integer) As String
Return instance_handler.Substring(start_index, length)
End Function

_
Public Function StripNonAlphanumeric(ByRef instance_handler As String, _
Optional ByVal replace_nonalphanumeric_with As String = Nothing, _
Optional ByVal nonalphanumeric_exceptions() As Char = Nothing) As String
Dim h As String = instance_handler.Trim
Dim s As New StringBuilder()
Dim c As Char
For i As Integer = 0 To h.Length – 1
c = h.Chars(i)
If Char.IsLetterOrDigit(c) = True Then
s.Append(c)
Else
If nonalphanumeric_exceptions IsNot Nothing AndAlso nonalphanumeric_exceptions.Contains(c) Then
s.Append(c)
ElseIf replace_nonalphanumeric_with IsNot Nothing Then
s.Append(replace_nonalphanumeric_with)
End If
End If
Next
Return s.ToString
End Function

_
Public Function StripAlphanumeric(ByRef instance_handler As String) As String
Dim h As String = instance_handler.Trim
Dim s As New StringBuilder()
Dim c As Char
For i As Integer = 0 To h.Length – 1
c = h.Chars(i)
If Char.IsLetterOrDigit(c) = False Then
s.Append(c)
End If
Next
Return s.ToString
End Function

_
Public Function StripAlphabetic(ByRef instance_handler As String) As String
Dim h As String = instance_handler.Trim
Dim s As New StringBuilder()
Dim c As Char
For i As Integer = 0 To h.Length – 1
c = h.Chars(i)
If Char.IsLetter(c) = False Then
s.Append(c)
End If
Next
Return s.ToString
End Function

_
Public Function StripNumeric(ByRef instance_handler As String) As String
Dim h As String = instance_handler.Trim
Dim s As New StringBuilder()
Dim c As Char
For i As Integer = 0 To h.Length – 1
c = h.Chars(i)
If Char.IsDigit(c) = False Then
s.Append(c)
End If
Next
Return s.ToString
End Function

_
Public Function StripNonNumeric(ByRef instance_handler As String) As String
Dim h As String = instance_handler.Trim
Dim s As New StringBuilder()
Dim c As Char
For i As Integer = 0 To h.Length – 1
c = h.Chars(i)
If Char.IsDigit(c) = True Then
s.Append(c)
End If
Next
Return s.ToString
End Function

_
Public Function StripPunctuation(ByRef instance_handler As String, _
Optional ByVal preserve_only_hyphenated_words As Boolean = False, _
Optional ByVal punctuation_exceptions() As Char = Nothing) As String
Dim h As String = instance_handler.Trim
Dim s As New StringBuilder()
Dim c As Char
Dim hyphens As List(Of Char) = New List(Of Char)(New Char() {"_"c, "-"c, "‐"c, "‒"c, "–"c, "—"c, "―"c})
For i As Integer = 0 To h.Length – 1
c = h.Chars(i)
If Char.IsPunctuation(c) = False Or (punctuation_exceptions IsNot Nothing AndAlso punctuation_exceptions.Contains(c)) Then
s.Append(c)
ElseIf preserve_only_hyphenated_words = True AndAlso hyphens.Contains(c) _
AndAlso i – 1 > -1 AndAlso i + 1 < h.Length _
AndAlso Char.IsLetterOrDigit(h.Chars(i – 1)) AndAlso Char.IsLetterOrDigit(h.Chars(i + 1)) Then
s.Append(c)
End If
Next
Return s.ToString
End Function

_
Public Function StripSpaces(ByRef instance_handler As String, Optional ByVal replace_space_with As String = "") As String
Dim h As String = instance_handler.Trim
Dim r As New Regex("(s+)", RegexOptions.Compiled And RegexOptions.IgnoreCase And RegexOptions.Singleline)
Dim s As String = r.Replace(h, replace_space_with)
r = Nothing
Return s
End Function

_
Public Function TrimSpaces(ByRef instance_handler As String, _
Optional StripSpaceAtStart As Boolean = True, _
Optional StripSpaceAtEnd As Boolean = True) As String
Dim h As String = instance_handler.Trim
Dim r As New Regex("(s+)", RegexOptions.Compiled And RegexOptions.IgnoreCase And RegexOptions.Singleline)
Dim s As String = r.Replace(h, " ")
If StripSpaceAtStart = True Then
s = s.TrimStart(" "c)
End If
If StripSpaceAtEnd = True Then
s = s.TrimEnd(" "c)
End If
r = Nothing
Return s
End Function

_
Public Function ReplaceGermanUmlauts(ByRef instance_handler As String) As String
Dim s As String = instance_handler
s = s.Replace("ä", "ae")
s = s.Replace("ö", "oe")
s = s.Replace("ü", "ue")
s = s.Replace("Ä", "Ae")
s = s.Replace("Ö", "Oe")
s = s.Replace("Ü", "Ue")
s = s.Replace("ß", "ss")
Return s
End Function

_
Public Function StripAccentMarks(ByRef instance_handler As String) As String
Dim n_s As String = instance_handler.Normalize(NormalizationForm.FormD)
Dim s As New StringBuilder()
Dim c As Char
For i As Integer = 0 To n_s.Length – 1
c = Convert.ToChar(n_s(i))
If System.Globalization.CharUnicodeInfo.GetUnicodeCategory(c) <> System.Globalization.UnicodeCategory.NonSpacingMark Then
s.Append(c)
End If
Next
Return s.ToString
End Function

_
Public Function StripTags(ByRef instance_handler As String) As String
Dim b As Boolean = False
Dim s As New StringBuilder()
Dim c As Char
For i As Integer = 0 To instance_handler.Length – 1
c = instance_handler.Chars(i)
If c = "<"c Then b = True
If Not b Then s.Append(c)
If c = ">"c Then b = False
Next
Return s.ToString
End Function

_
Public Function SpecialCharsToHtmlEntities(ByRef instance_handler As String) As String
Return HttpUtility.HtmlEncode(instance_handler)
End Function

_
Public Function HtmlEntitiesToSpecialChars(ByRef instance_handler As String) As String
Return HttpUtility.HtmlDecode(instance_handler)
End Function

_
Public Function Pad(ByRef instance_handler As String, ByVal length As Integer, Optional ByVal padding_char As Char = " "c) As String
Dim s As String = String.Empty
If length > instance_handler.Length Then
s = instance_handler.PadLeft(length, padding_char)
Else
s = instance_handler.Substring(length – 1)
End If
Return s
End Function

_
Public Function Pad(ByRef instance_handler As Integer, ByVal length As Integer, Optional ByVal padding_char As Char = "0"c) As String
Dim s As String = String.Empty
Dim nb As String = instance_handler.ToString
If length > nb.Length Then
s = nb.PadLeft(length, padding_char)
Else
s = nb.Substring(length – 1)
End If
Return s
End Function

End Module

End Namespace
[/sourcecode]