render – MaxVergelli.com https://www.maxvergelli.com sourcecode repository Sat, 11 Apr 2020 15:54:53 +0000 en-US hourly 1 https://i2.wp.com/www.maxvergelli.com/wp-content/uploads/2020/04/wp-1586823685141.png?fit=32%2C32&ssl=1 render – MaxVergelli.com https://www.maxvergelli.com 32 32 34603511 Render a Section in a Partial View – ASP.Net MVC https://www.maxvergelli.com/render-a-section-in-a-partial-view-asp-net-mvc/ https://www.maxvergelli.com/render-a-section-in-a-partial-view-asp-net-mvc/#respond Sun, 12 Apr 2020 15:34:00 +0000 https://www.maxvergelli.com/?p=231 Read More]]> Let’s start with the following configuration to give an example: in a MVC project, you have a “_Layout.vbhtml” file with this code

<!DOCTYPE html>
<html>
  <head>
  </head>
  <body>
	<!-- some code here -->
    <script src="@Url.Content("~/Scripts/jquery-1.8.2.min.js")">		</script>
    @RenderSection("Scripts", false)
  </body>
</html>

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

@Section Scripts
    <script src="@Url.Content("~/Scripts/jquery.validate.min.js")"></script>
    <script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")"></script>
    <script src="@Url.Content("~/Scripts/jquery.validate.fix.js")"></script>  
    <script src="@Url.Content("~/Scripts/localization/messages_de.js")"></script>      
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")

<h2>Just a Test</h2>

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

<!DOCTYPE html>
<html>
  <head>
  </head>
  <body>
    
    <script src="@Url.Content("~/Scripts/jquery-1.8.2.min.js")"></script>

  </body>
</html>

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<string> scriptList = htmlHelper.ViewContext.HttpContext
      .Items[HtmlHelperExtensions._jSViewDataName] as List<string>;
    if (scriptList != null)
    {
      if (!scriptList.Contains(scriptURL))
      {
        scriptList.Add(scriptURL);
      }
    }
    else
    {
      scriptList = new List<string>();
      scriptList.Add(scriptURL);
      htmlHelper.ViewContext.HttpContext
        .Items.Add(HtmlHelperExtensions._jSViewDataName, scriptList);
    }
  }

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

    List<string> scriptList = HtmlHelper.ViewContext.HttpContext
      .Items[HtmlHelperExtensions._jSViewDataName] as List<string>;
    if (scriptList != null)
    {
      foreach (string script in scriptList)
      {
        result.AppendLine(string.Format(
          "<script type=\"text/javascript\" src=\"{0}\"></script>", 
          script));
      }
    }

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

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

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

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

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

   if (styleList != null)
   {
     foreach (string script in styleList)
     {
       result.AppendLine(string.Format(
         "<link href=\"{0}\" rel=\"stylesheet\" type=\"text/css\" />", 
         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…

<!DOCTYPE html>
<html lang="en">
  <head>
  @Html.RenderStyles()
  @Html.RenderJavascripts()

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