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Editorial Team
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Asked: 2026-06-07T10:03:28+00:00

I am trying to post the data to cross domain. It works fine if

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I am trying to post the data to cross domain. It works fine if the form is not using runat=”server” and its giving 500 internal error while posting when the form is using runat=”server”.

Upon debugging, I identified that the problem is with auto generated __viewstate code on the page. Please find the below code.

Clientside HTML implementation:

<%@ Page Language="C#" CodeFile="Sample.aspx.cs" Inherits="Sample" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<meta charset="utf-8">
    <title>Untitled Page</title>
    <link href="FileUpload.css" rel="stylesheet" type="text/css" />

   <script id="template-upload" type="text/x-tmpl">
    </script>
    <script id="template-download" type="text/x-tmpl">
    </script>

    <script src="../../test/FileUpload/jQueryv1.6.2.js"></script>
    <script src="fileupload-js/jquery.ui.widget.js"></script>
    <script src="fileupload-js/tmpl.min.js"></script>
    <script src="fileupload-js/jquery.fileupload.js"></script>
    <script src="fileupload-js/jquery.fileupload-ui.js"></script>
    <script src="fileupload-js/locale.js"></script>
    <script src="fileupload-js/main.js"></script>    
</head>
<body>
<form id="fileupload" method="POST" runat="server">
    <CCAB.Web:FileUpload runat="server"/>
</form>
</body>
</html>

Serverside code:

public partial class SaveFile : System.Web.UI.Page
{
    private void Page_Load(object sender, System.EventArgs e)
    {
        Response.AddHeader("Access-Control-Allow-Origin", "*")

        if (Request.HttpMethod == "GET" || Request.HttpMethod == "HEAD")
        {

            Response.Write("GET Success");
        }
        else
        {
            for (int i = 0; i < Request.Files.Count; i++)
            {
                string filename = Request.Files[i].FileName;
                Request.Files[i].SaveAs(@"\\dev2\\share$\\Anna\\test\\" + filename);
                Response.Write(filename);
            Response.Write("Success");
            }

        }
    }
}

Could you please help me in how to ignore the hidden viewstate code from client side or ignore the response viewstate in server side.

Many Thanks
Anna

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1 Answer

  1. Editorial Team

    I have found the solution for this problem. Please find below

    public class BasePage : Page

{

  private static string[] aspNetFormElements = new string[] 

  { 

    "__EVENTTARGET",

    "__EVENTARGUMENT",

    "__VIEWSTATE",

    "__EVENTVALIDATION",

    "__VIEWSTATEENCRYPTED",

  };



  protected override void Render(HtmlTextWriter writer)

  {

    StringWriter stringWriter = new StringWriter();

    HtmlTextWriter htmlWriter = new HtmlTextWriter(stringWriter);

    base.Render(htmlWriter);

    string html = stringWriter.ToString();

    int formStart = html.IndexOf("<form");

    int endForm = -1;

    if (formStart >= 0)

      endForm = html.IndexOf(">", formStart);



    if (endForm >= 0)

    {

      StringBuilder viewStateBuilder = new StringBuilder();

      foreach (string element in aspNetFormElements)

      {

        int startPoint = html.IndexOf("<input type=\"hidden\" name=\"" + element + "\"");

        if (startPoint >= 0 && startPoint > endForm)

        {

          int endPoint = html.IndexOf("/>", startPoint);

          if (endPoint >= 0)

          {

            endPoint += 2;

            string viewStateInput = html.Substring(startPoint, endPoint - startPoint);

            html = html.Remove(startPoint, endPoint - startPoint);

            viewStateBuilder.Append(viewStateInput).Append("\r\n");

          }

        }

      }



      if (viewStateBuilder.Length > 0)

      {

        viewStateBuilder.Insert(0, "\r\n");

        html = html.Insert(endForm + 1, viewStateBuilder.ToString());

      }

    }



    writer.Write(html);

  }

}

    Please find more info on this page : http://blogs.msdn.com/b/tom/archive/2008/03/14/validation-of-viewstate-mac-failed-error.aspx

    Many Thanks
    Anna

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