Please know that I’m a complete noob without any kind of web dev experience. This also seems like something that would be wanted pretty frequently, so I very well might be missing something simple in my too-many hours of Googling.

I have a web form with some text boxes for user info and an AjaxFileUpload control. I want to check that a TextBox is filled in when the “Upload” button in the AdjaxFileUpload control is hit.

I’m successfully using the OnClientUploadCompleteAll of the upload control and a Java function that triggers and a hidden button to do some things after the upload.

I was hoping to use the OnClientUploadStart to do something similar for checking the TextBox. The commented code below are things I’ve tried after searching around for things, but with no joy. I’m also thinking there may not be a way to do this because when the JSUpldStart function fires the “Upload” button has already turned into a “Cancel” button in the upload control.

I’ve tried playing with some asp.net validation things but couldn’t make those work. Again, noob, was probably missing something as I only had validation happening AFTER the upload and it was cancelling the post upload code that had been working. :o/

Thanks for reading.

<ajaxToolkit:AjaxFileUpload ID="AjaxFileUpload1" runat="server" 
    OnUploadComplete="AjaxFileUpload1_UploadComplete"
    OnClientUploadCompleteAll="JSUpldDoneAll"
    OnClientUploadStart="JSUpldStart"
    Width="50%" />

function JSUpldStart(sender, args) {
    /*alert("JSUPldStart")*/
    if (TxtUplBy.value == "") {
        alert("It's blank.")
        /*args.cancel(true);    Cancel is not a function*/
        //throw ("Please fill in name.");
        //return false;
        //args.set_cancel(True);        Error: True is not defined
        //args.set_cancel(true);        Error: set_cancel is not a function
        //args.set_cancel=true          Did absolutely nothing.
    }
}