Comments by bobishkindaguy (Top 18 by date)

I got it working, much appreciated. There were a couple of more things that had to be done so I thought I'd update this with that.

1. I had to add this, as you suggested. It needed to go in the site.master:
"multipart/form-data"

2. I added runat="server" to the "Uploader"markup -- which as you said made it into a "HtmlControls.HtmlGenericControl" in the default.aspx designer code file.

3. Then I had to add the following to the default.aspx markup file. (includes code for providing debug feedback)

<%@ Implements Interface="System.Web.UI.ICallbackEventHandler" %>



Dim _cbMessage As String = ""
'Method that processes the callbacks on server.
Public Sub RaiseCallbackEvent(ByVal eventArgument As String) _
Implements System.Web.UI.ICallbackEventHandler.RaiseCallbackEvent

Try
Page.ClientScript.ValidateEvent(Uploader1.UniqueID, Me.ToString())
_cbMessage = "Correct event raised callback."

Catch ex As Exception
_cbMessage = "Incorrect event raised callback."

End Try

End Sub

'Method that returns callback result.
Public Function GetCallbackResult() As String Implements System.Web.UI.ICallbackEventHandler.GetCallbackResult
Return _cbMessage
End Function


Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)
If (Not IsPostBack) Then
Dim CM As ClientScriptManager = Page.ClientScript
Dim CallBackRef As String = CM.GetCallbackEventReference("'" & Page.UniqueID & "'", "arg", "ReceiveServerData", "", "ProcessCallBackError", False)
Dim CallbackScript As String = "function CallTheServer(arg, context) {" & CallBackRef & "; }"
CM.RegisterClientScriptBlock(Me.GetType(), "CallTheServer", CallbackScript, True)
End If
End Sub

Protected Overrides Sub Render(ByVal writer As System.Web.UI.HtmlTextWriter)
Page.ClientScript.RegisterForEventValidation(Uploader1.UniqueID, Me.ToString())
MyBase.Render(writer)
End Sub




var value1 = new Date();
function ReceiveServerData(arg, context)
{
Message.innerText = arg;
Label1.innerText = "Callback completed at " + value1;
value1 = new Date();
}
function ProcessCallBackError(arg, context)
{
Message.innerText = 'An error has occurred.';
}