ASP.NET-回传后，CustomValidator无法正常工作

Question

I have a simple case.

A custom validator in page Default.aspx

<asp:UpdatePanel ID="UplTab1" runat="server" >
    <ContentTemplate>   
        <span>
            <asp:TextBox ID="MyTextBox" runat="server" Width="400px"></asp:TextBox>
            <asp:CustomValidator Display="Dynamic" ID="MyValidator" runat="server" ErrorMessage="Mon message" ControlToValidate="MyTextBox" OnServerValidate="MyValidator_OnServerValidate" ValidationGroup="MyGroup1"></asp:CustomValidator>
        </span>     
        <span>
            <asp:Button ID="BtnSave" runat="server" Text="Save" ValidationGroup="MyGroup1" OnClick="BtnSave_OnClick"></asp:Button>
        </span>                     
    </ContentTemplate>
</asp:UpdatePanel>

Default.aspx.cs

protected void Page_Load(object sender, EventArgs e)
{
}

protected void MyValidator_OnServerValidate(object source, ServerValidateEventArgs args)
{
    args.IsValid = MyValidationFunction();
}

When I try to validate my textbox control, no problem it works, my function "MyValidator_OnServerValidate" is fired. Then I try to re-submit my form again with same button with a different value in my textbox, but this time my custom validator doesn't work anymore.

My question is why this behavior?

I think it's the postback behavior because if I refresh my page, the custom validator works.

Answer 1

I had exactly the same symptoms. CustomValidator and UpdatePanel acts funny when you have javaScript errors. It may be some innocent javaScript error but it will stop Ajax request to complete. To test that check whether your ajax postback end request is fired correctly.

$(function () {
    Sys.WebForms.PageRequestManager.getInstance().add_endRequest(EndRequestHandler);                        
});

function EndRequestHandler(sender, args) {
    alert('Postback!');
}