Elegant way to make CustomValidator work with ValidationSummary messagebox

Question

I have run into this problem before but never quite solved it. I have a form with several validators and also a CustomValidator.

Answer 1

This worked for me:

<asp:CustomValidator runat="server" ID="cv" 
ClientValidationFunction="ValidateFunction"
ErrorMessage="Default error
message">*</asp:CustomValidator>

<script type="text/javascript">
function ValidateFunction(sender, args) 
{

var msg ='';
var formValid = true;

[various checks setting msg and formValid]

if (msg.length > 0) { sender.errormessage = msg; }
args.IsValid = formValid;

}
</script>