Problems with AsyncFileUpload because of one Session per Control

I have had the following problem with AsyncFileUpload from Ajax Toolkit:

• One aspx-Page with one asyncfileupload control
• Same user could open the page severval times at the same time
• Problem only one session value for all page instances!

I have found out that the client id was the key to the problem and have inherited from the standard class and have overridden the important properties:

   1: public class ExtendedAsyncFileUpload : AsyncFileUpload

   2:     {

   3:         private string newClientID = null;

   4:         private string newUniqueID = null;

   5:  

   6:  

   7:         /// <summary>

   8:         /// Unique ID for session of a user

   9:         /// </summary>

  10:         protected string SessionUniqueControlIdentifier

  11:         {

  12:             get

  13:             {

  14:                 if (string.IsNullOrEmpty(ViewState["SessionUniqueControlIdentifier"] as string))

  15:                     ViewState["SessionUniqueControlIdentifier"] = Guid.NewGuid().ToString().Replace("-", "");

  16:                 return ViewState["SessionUniqueControlIdentifier"] as string;

  17:             }

  18:         }

  19:  

  20:         protected override void OnPreRender(EventArgs e)

  21:         {

  22:             base.OnPreRender(e);

  23:         }

  24:  

  25:  

  26:         public override string ClientID

  27:         {

  28:             get

  29:             {

  30:  

  31:                 if (string.IsNullOrEmpty(newClientID))

  32:                     newClientID = UniqueID.Replace("$", "_");

  33:                 return newClientID;

  34:             }

  35:         }

  36:  

  37:         public override string UniqueID

  38:         {

  39:             get

  40:             {

  41:                 if (string.IsNullOrEmpty(newUniqueID) && !base.UniqueID.EndsWith(this.SessionUniqueControlIdentifier))

  42:                     newUniqueID = base.UniqueID + this.SessionUniqueControlIdentifier;

  43:                 return newUniqueID;

  44:             }

  45:         }

  46:  

  47:         /// <summary>

  48:         /// Overriden because, original method catches all exceptions, no matter what...

  49:         /// </summary>

  50:         public byte[] FileBytesNew

  51:         {

  52:             get

  53:             {

  54:                 HttpPostedFile file = base.PostedFile;

  55:                 if (file != null)

  56:                     return this.GetBytesFromStream(file.InputStream);

  57:                 else

  58:                     return null;

  59:             }

  60:         }

  61:  

  62:     }