Question

This thing is drive me crazy. I’m trying to intercept an exception server-side, during a partial postback, setting an error message to show on the client in a javascript alert.

But I just receive the following error on the firefox console:

uncaught exception: [Exception... "'Sys.WebForms.PageRequestManagerServerErrorException: Sys.WebForms.PageRequestManagerServerErrorException: Tentativo di divisione per zero.' when calling method: [nsIDOMEventListener::handleEvent]" nsresult: "0x8057001c (NS_ERROR_XPC_JS_THREW_JS_OBJECT)" location: "JS frame :: resource://firebug_rjs/net/spy.js :: callPageHandler :: line 796" data: no]

and no alert at all.

I got this problem on a complex project that involves Telerik components, but I’ve reduced the problem to its fundamentals, following this simple example, and the problem still exists.

The case:

Default.aspx

<form id="form1" runat="server">
<asp:ScriptManager ID="scriptManager" runat="server" OnAsyncPostBackError="scriptManager_OnAsyncPostBackError"></asp:ScriptManager>
<div>
    <asp:UpdatePanel ID="upd" runat="server">
        <ContentTemplate>
            <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
            <asp:TextBox ID="TextBox2" runat="server"></asp:TextBox>
            <asp:Button ID="btnSend" runat="server" Text="Send" OnClick="btnSend_OnClick" />
        </ContentTemplate>
    </asp:UpdatePanel>
</div>
</form>

Default.aspx.cs

protected void scriptManager_OnAsyncPostBackError(object sender, AsyncPostBackErrorEventArgs e) 
{
    scriptManager.AsyncPostBackErrorMessage = e.Exception.Message;
}

protected void btnSend_OnClick(object sender, EventArgs e) 
{
    // this will throw and Exception
    int aa = Convert.ToInt32(TextBox1.Text) / Convert.ToInt32(TextBox2.Text);
}

I’ve tried with VS2010/.NET 4.0 and with VS2008/.NET 3.5, in Firefox and Internet Explorer, the problem is the same.

Please, anyone has some idea?

Answer 1

In addition to handling logic on server side you have to add script in order to handle error on client side.

 <script>
        Sys.WebForms.PageRequestManager.getInstance().add_endRequest(EndRequestHandler);
        function EndRequestHandler(sender, args) {
            if (args.get_error() != undefined) {
                alert(args.get_error());
            }
        }
    </script>

This script is handling end_Request event, and if there was some error fires alert.