WebControl.AddAttributesToRender Method (HtmlTextWriter)


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Adds HTML attributes and styles that need to be rendered to the specified HtmlTextWriterTag. This method is used primarily by control developers.

Namespace:   System.Web.UI.WebControls
Assembly:  System.Web (in System.Web.dll)

Protected Overridable Sub AddAttributesToRender (
	writer As HtmlTextWriter


Type: System.Web.UI.HtmlTextWriter

A HtmlTextWriter that represents the output stream to render HTML content on the client.

To render attributes and styles for a Web Server control on the client, you typically call the AddAttribute and HtmlTextWriter.AddStyleAttribute methods to insert each attribute and style individually to the HtmlTextWriter output stream. To simplify the process, this method encapsulates all calls to the HtmlTextWriter.AddAttribute and HtmlTextWriter.AddStyleAttribute methods for every attribute and style associated with the Web server control. All attributes and styles are inserted into the HtmlTextWriter output stream in a single method call. This method is typically overridden by control developers in derived classes to insert the appropriate attributes and styles to the HtmlTextWriter output stream for the class.


The AddAttributesToRender method cannot be used to insert client script. To use client script, see the ClientScriptManager class.

The following example demonstrates how to create a class that derives from the WebControl class. The base implementation of the AddAttributesToRender method is overridden to add attributes appropriate to the derived class in the HtmlTextWriter output stream.

Imports System
Imports System.Web.UI
Imports System.Web.UI.WebControls

Namespace ControlTest

   ' Renders the following HTML: 
   ' <span onclick="alert('Hello');" style="color:Red;">Custom Contents</span>
   Public Class MyWebControl
      Inherits WebControl

      Public Sub New()
      End Sub 'New      

      <System.Security.Permissions.PermissionSetAttribute(System.Security.Permissions.SecurityAction.Demand, Name:="FullTrust")> _
      Protected Overrides Sub AddAttributesToRender(writer As HtmlTextWriter)

         writer.AddAttribute(HtmlTextWriterAttribute.Onclick, "alert('Hello');")
         writer.AddStyleAttribute(HtmlTextWriterStyle.Color, "Red")

      End Sub 'AddAttributesToRender       

      <System.Security.Permissions.PermissionSetAttribute(System.Security.Permissions.SecurityAction.Demand, Name:="FullTrust")> _
      Protected Overrides Sub RenderContents(writer As HtmlTextWriter)
         writer.Write("Custom Contents")
      End Sub 'RenderContents

   End Class 'MyWebControl

End Namespace 'ControlTest

.NET Framework
Available since 1.1
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