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System.Threading.ThreadAbortException when you use Server.Transfer in HTTPHandler in an ASP.NET application

This article helps you resolve the problem that an error might be thrown when you use a Server.Transfer method in HTTPHandler to transfer the control from one page to another in an ASP.NET web application.

Original product version:   ASP.NET
Original KB number:   817266

Symptoms

When you use a Server.Transfer method in HTTPHandler to transfer the control from one page to another in an ASP.NET web application, you might receive the following error message:

System.Threading.ThreadAbortException: Thread was being aborted. at
System.Threading.Thread.AbortInternal() at System.Threading.Thread.Abort() at
System.Threading.Thread.Abort(Object stateInfo) at System.Web.HttpResponse.End() at
System.Web.HttpServerUtility.Transfer(String path, Boolean preserveForm)

Cause

When you call Server.Transfer, ASP.NET internally calls the Server.Execute method to transfer the control, and calls the Response.End method to end the processing of the current page. Response.End ends the page execution and calls the Thread.Abort method. The Thread.Abort method causes the ThreadAbortException error message to appear.

Workaround

To work around this problem, use Server.Execute instead of Server.Transfer in the ProcessRequest method of HTTPHandler. The modified ProcessRequest method is as follows:

  • C# sample code

    public void ProcessRequest(HttpContext context)
{
    try
    {
       context.Server.Execute("WebForm1.aspx");
    }
    catch(System.Exception e)
    {
       context.Response.Write(e.StackTrace);
       context.Response.Write(e.ToString());
    }
}

  • Visual Basic sample code

    Public Sub ProcessRequest(ByVal context As HttpContext) _
       Implements IHttpHandler.ProcessRequest
    Try
       context.Server.Execute("WebForm1.aspx")
    Catch e As Exception
       context.Response.Write(e.StackTrace)
    End Try
End Sub

Status

This behavior is by design.

Steps to reproduce the behavior

  1. In Microsoft Visual Studio, use Visual Basic or C# to create a new ASP.NET Web Forms Application project. By default, WebForm1.aspx is created. Name the project ServerTransferTest.

  2. Right-click WebForm1.aspx and then select View HTML Source.

  3. Replace the existing code with the following sample code:

    <%@ Page %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
   <HEAD>
      <title>WebForm1</title>
   </HEAD>
   <body MS_POSITIONING="GridLayout">
      <form id="Form1" method="post" runat="server">
         <asp:HyperLink id="HyperLink1" style="Z-INDEX: 101; LEFT: 324px; POSITION: absolute; TOP: 181px" runat="server" NavigateUrl="http://localhost/ServerTransferTest/test.ashx"> http://localhost/ServerTransferTest/test.ashx</asp:HyperLink>
         <asp:Label id="Label1" style="Z-INDEX: 102; LEFT: 292px; POSITION: absolute; TOP: 149px" runat="server">On Clicking this URL should not throw any exception</asp:Label>
      </form>
   </body>
</HTML>

  4. Double-click Design View of WebForm1.aspx, and then replace the exiting code in the code behind page with the following sample code:

    • C# sample code

      using System;
using System.Web;
using System.Web.UI.WebControls;

namespace ServerTransferTest
{
   /// <summary>
   /// Summary description for WebForm1.
   /// </summary>
   public class WebForm1 : System.Web.UI.Page
   {
      protected System.Web.UI.WebControls.Label Label1;
      protected System.Web.UI.WebControls.HyperLink HyperLink1;

      private void Page_Load(object sender, System.EventArgs e)
      {
      }

      #region Web Form Designer generated code
      override protected void OnInit(EventArgs e)
      {
         // CODEGEN: ASP.NET Web Form Designer requires this call.
         InitializeComponent();
         base.OnInit(e);
      }

      /// <summary>
      /// Required method for Designer support - do not modify
      /// the contents of this method by using the code editor.
      /// </summary>
      private void InitializeComponent()
      {
         this.Load += new System.EventHandler(this.Page_Load);    
      }
      #endregion
   }
}

    • Visual Basic sample code

      Public Class WebForm1
    Inherits System.Web.UI.Page
    Protected WithEvents Label1 As System.Web.UI.WebControls.Label
    Protected WithEvents HyperLink1 As System.Web.UI.WebControls.HyperLink

    'Web Form Designer requires this call.
    <System.Diagnostics.DebuggerStepThrough()>
    Private Sub InitializeComponent()
    End Sub

    Private Sub Page_Init(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Init
       'CODEGEN: Web Form Designer requires this method call.
       'Do not modify it by using the code editor.
       InitializeComponent()
    End Sub

    Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
       'Put user code to initialize the page here
    End Sub
End Class

  5. On the File menu, select Add New Item.

  6. Under Add New Item, select Class. In the Name text box under Add New Item, rename the class HelloWorldHandler, and then select Open.

  7. Replace the existing code in the HelloWorldHandler class file with the following sample code:

    • C# sample code

      using System.Web;
namespace ServerTransferTest
{
    public class HelloWorldHandler : IHttpHandler
    {
       public void ProcessRequest(HttpContext context)
       {
          try
          {
             context.Server.Transfer("WebForm1.aspx", true );
          }
          catch(System.Exception e)
          {
             context.Response.Write(e.StackTrace);
             context.Response.Write(e.ToString());
          }
       }
       public bool IsReusable
       {
          // To enable pooling, return true here.
          // This keeps the handler in memory.
          get { return false; }
       }
    }
}

    • Visual Basic sample code

      Imports System
Imports System.Web

Public Class HelloWorldHandler
    Implements IHttpHandler
    Public Sub ProcessRequest(ByVal context As HttpContext) _
       Implements IHttpHandler.ProcessRequest
       Try
          ' context.Server.Transfer("WebForm1.aspx", True)
          context.Server.Execute("WebForm1.aspx")
       Catch e As Exception
          context.Response.Write(e.StackTrace)
       End Try
    End Sub
    ' Override the IsReusable property.
    Public ReadOnly Property IsReusable() As Boolean _
       Implements IHttpHandler.IsReusable
       Get
          Return True
       End Get
    End Property
End Class

  8. Repeat steps 5 and 6 to add another class file. Rename the class file HelloWorldHandlerFactory.

  9. Replace the existing code in the HelloWorldHandlerFactory class file with the following sample code:

    • C# sample code

      using System.Web;
namespace ServerTransferTest
{
    public class HelloWorldHandlerFactory : IHttpHandlerFactory
    {
       public IHttpHandler GetHandler( HttpContext context, System.String requestType, System.String url, System.String pathTranslated)
       {
          HttpResponse Response = context.Response;
          Response.Write("<html>");
          Response.Write("<body>");
          Response.Write("<h1> Hello from HelloWorldHandlerFactory.GetHandler </h1>");
          Response.Write("</body>");
          Response.Write("</html>");
          return new HelloWorldHandler();
       }
       public void ReleaseHandler( IHttpHandler handler )
       {
       }
    }
}

    • Visual Basic sample code

      Imports System
Imports System.Web
Public Class HelloWorldHandlerFactory
    Implements IHttpHandlerFactory
    Public Overridable Function GetHandler(ByVal context As HttpContext, _
    ByVal requestType As String, ByVal url As String, ByVal pathTranslated As String) _
       As IHttpHandler _
       Implements IHttpHandlerFactory.GetHandler

       Dim Response As HttpResponse = context.Response
       Response.Write("<html>")
       Response.Write("<body>")
       Response.Write("<h1> Hello from HelloWorldHandlerFactory.GetHandler </h1>")
       Response.Write("</body>")
       Response.Write("</html>")
       Return New HelloWorldHandler()
    End Function

    Public Overridable Sub ReleaseHandler(ByVal handler As IHttpHandler) _
       Implements IHttpHandlerFactory.ReleaseHandler
    End Sub
End Class

  10. Open the web.config file, and then add the <httpHandlers> section in the <system.web> section as follows:

    <configuration>
    <system.web>
        <httpHandlers>
            <add verb="*" path="*.ashx" type="ServerTransferTest.HelloWorldHandlerFactory,ServerTransferTest" />
        </httpHandlers>
    .....
    </system.web>
</configuration>

  11. On the Debug menu, select Start, and then select the following hyperlink on WebForm1.aspx:

    http://localhost/ServerTransferTest/test.ashx

References