UploadControl - Uploading an empty file into Azure results in the "BadRequest RequestResult: InvalidHeaderValueThe value for one of the HTTP headers is not in the correct format." error

Hello,

I was able to reproduce this issue and passed this ticket to our developers for further research.
We will update this ticket as soon as we get results.

Regarding your question about error handling - there are no such error handlers on the client side but you can handle these errors in Global.asax, for example, the following code will display the "Cloud upload failed." string:

C#
protected void Application_Start()  
{  
    ...  
    DevExpress.Web.ASPxWebControl.CallbackError += Application_Error;  
}  
 protected void Application_Error(object sender, EventArgs e)  
{  
    var exception = HttpContext.Current.Server.GetLastError();  
    if (exception.Message.Contains("Bad request"))  
        DevExpress.Web.ASPxWebControl.SetCallbackErrorMessage("Cloud upload failed.");  
}  

Please refer to the Handling Callback Exceptions on Server | ASP.NET Controls and MVC Extensions | DevExpress Help documentation article to learn how to handle errors in the Global.asax file.

Hi,
I tried your solution to update the error message but the Application_Error would not get hit on a CallbackError.
When I try to upload an empty file with a breakpoint in the Application_Error method, the breakpoint will not get hit and the message will stay as it originally was.
I would upload a demo project but it won't let me upload a file more than 30MB

Hello,

To process your recent post more efficiently, I created a separate ticket on your behalf: T296086: CallbackError event handler is not invoked on callback error. This ticket is currently in our processing queue. Our team will address it as soon as we have any updates.