I'm trying to catch and clear an error in ASP.net but I get redirected to "The connection to the server was reset while the page was loading"

I've got a page that lets you upload files. I've increased the maximum filesize to the desired level and that works but I would like to have customised error handling for when the user uploads something too big.

All the guides I've found so far give advice on how to redirect to a specal error page, I can't find anything on how to just present the error in a current page. Here's what I'm using so far.

protected override void OnError(EventArgs e)
{
    HttpContext hcCurrentContext = HttpContext.Current;

    Exception eException = this.Server.GetLastError();

    if (eException.Message.Equals("Maximum request length exceeded."))
    {
        hcCurrentContex开发者_如何学运维t.Server.ClearError();
        tbErrorMessage.Text = "File too large";
        tbErrorMessage.Visible = true;
    }
    else
    {
        base.OnError(e);
    }
}

I ran it through a debugger and it does go into the If clause correctly, but I still get redirected to the default FireFox error page with the message "The connection to the server was reset while the page was loading". Can anyone advise me?

---

Trapping exceptions that arise when large files are uploaded is hard, as there are inbuilt checks in IIS to prevent denial-of-service attacks that cause these exceptions to be generated.

See Jon Galloway's post for details on how to get around this. In essence you'll need to

• Attempt reconfiguration of IIS to handle larger files
• Try an third-party component that allows larger files
• Trap HTTP 400 in IIS - which isn't ideal, as the 400 code can happen in other circumstances.