<asp:ScriptManager ID="ScriptManager1" runat="server"
AsyncPostBackTimeOut="600">
</asp:ScriptManager>

ScriptManagerInstanceID.AsyncPostBackTimeout = 600;

<script type="text/javascript">
Sys.WebForms.PageRequestManager.getInstance().add_endRequest(requestEndHandler );
 
// This function will handle the end request event
function requestEndHandler(sender, args) {
   if( args.get_error() ){
      document.getElementById("errorMessageLabel").innerText = 
         args.get_error().description;
      args.set_errorHandled(true);
   }
}
 
</script>
...
 
<div id="errorMessageLabel"></div>

namespace Unicodeinfo
  {
      public partial class Unicodefrm : Form
      {
         public Unicodefrm()
         {
            InitializeComponent();
         }
 
        // assign Unicode strings to each Label
        private void Unicodefrm_Load( object sender, EventArgs e )
        {
           // English
           char[] english = { '\u0057', '\u0065', '\u006C',
              '\u0063', '\u006F', '\u006D', '\u0065', '\u0020',
              '\u0074', '\u006F', '\u0020' };
           englishLabel.Text = new string( english ) +
              "Unicode" + '\u0021';
 
               // French
              char[] french = { '\u0042', '\u0069', '\u0065',
                 '\u006E', '\u0076', '\u0065', '\u006E', '\u0075',
                 '\u0065', '\u0020', '\u0061', '\u0075', '\u0020' };
              frenchLabel.Text = new string ( french ) +
                 "Unicode" + '\u0021' ;
 
              // German
              char[] german = { '\u0057', '\u0069', '\u006C',
                 '\u006B', '\u006F', '\u006D', '\u006D', '\u0065',
                 '\u006E', '\u0020', '\u007A', '\u0075', '\u0020' };
              germanLabel.Text = new string ( german ) +
                 "Unicode" + '\u0021';
 
              // Japanese
              char[] japanese = { '\u3078',  '\u3087', '\u3045',
                 '\u3053', '\u305D', '\u0021'};
              japaneseLabel.Text = "Unicode" + new string( japanese );
 
              // Portuguese
              char[] portuguese = { '\u0053', '\u0065', '\u006A',
                 '\u0061', '\u0020', '\u0062', '\u0065', '\u006D',
                 '\u0020', '\u0076', '\u0069', '\u006E', '\u0064',
                 '\u006F', '\u0020', '\u0061', '\u0020' };
              portugueseLabel.Text = new string ( portuguese ) +
                 "Unicode" + '\u0021';
 
               // Russian
              char[] russian = { '\u0414', '\u043E', '\u0431',
                 '\u0440', '\u043E', '\u0020', '\u043F', '\u043E',
                 '\u0436', '\u0430', '\u043B', '\u043E', '\u0432',
                 '\u0430', '\u0442', '\u044A', '\u0020', '\u0432', '\u0020' };
              russianLabel.Text = new string ( russian ) +
                 "Unicode" + '\u0021';
 
               // Spanish
              char[] spanish = { '\u0042', '\u0069', '\u0065',
                 '\u006E', '\u0076', '\u0065', '\u006E', '\u0069',
                 '\u0064', '\u006F', '\u0020', '\u0061', '\u0020'};
              spanishLabel.Text = new string ( spanish ) +
                  "Unicode" + '\u0021';
 
               // Simplified Chinese
              char[] chinese = { '\u6B22', '\u8FCE', '\u4F7F',
                 '\u7528', '\u0020'};
              chineseLabel.Text = new string ( chinese ) +
                 "Unicode" + '\u0021';
           } // end method Unicodefrm_Load
        } // end class Unicodefrm
    } // end namespace Unicodeinfo

static byte[] HashXml ( XmlElement xe, HashAlgorithm hash ) 
{ 
    XmlDocument xd = new XmlDocument(); 
    xd.LoadXml (xe.OuterXml); 
    return HashXml(xd, hash); 
}

static byte[] HashXml ( XmlDocument xd, HashAlgorithm hash ) 
{ 
   //Get the assembly
    Assembly a = Assembly.Load("System.Security, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"); 
 
    //Get the hashing class 
 
    Type t = a.GetType("System.Security.Cryptography.Xml.CanonicalXml"); 
 
    ConstructorInfo c = t.GetConstructor(
        BindingFlags.Instance | BindingFlags.NonPublic, 
        null, 
        new Type[] { typeof(XmlDocument), typeof(XmlResolver) }, 
        null); 
 
    //construct the object
    object cx = c.Invoke(new object[] { xd, null }); 
 
    //calculate the Hash 
    byte[] result = (byte[])t.InvokeMember(
        "GetDigestedBytes",
        BindingFlags.InvokeMethod | BindingFlags.NonPublic | BindingFlags.Instance, 
        null, 
        cx, 
        new object[] { hash }); 
 
    return result; 
}