Question

I have three textboxes and I want to validate them. At least one textbox must contain data.

How can I do this?

(The textboxes are Home Phone No., Work Phone No., Mobile No. and I need to check at least one method of contact is specified)

Answer 1

Use a Custom Validator, there is no need to cycle through the text boxes on the page as this approach gets ALL of the text boxes on the page. The JavaScript function specified in the ClientValidationFunction will be called for each text box with a validator associated with it.

<asp:TextBox ID="txtHomePhone" runat="server"></asp:TextBox>
<asp:CustomValidator ID="cvHomePhone" runat="server" ErrorMessage="*" ClientValidationFunction="Validate" ControlToValidate="txtHomePhone"  ValidateEmptyText="true"></asp:CustomValidator>


<asp:TextBox ID="txtWorkPhone" runat="server"></asp:TextBox>
<asp:CustomValidator ID="cvWorkPhone" runat="server" ErrorMessage="*" ClientValidationFunction="Validate" ControlToValidate="txtWorkPhone"  ValidateEmptyText="true"></asp:CustomValidator>


<asp:TextBox ID="txtMobilePhone" runat="server"></asp:TextBox>
<asp:CustomValidator ID="cvMobilePhone" runat="server" ErrorMessage="*" ClientValidationFunction="Validate" ControlToValidate="txtMobilePhone"  ValidateEmptyText="true"></asp:CustomValidator>


<script language="javascript">
function Validate(sender, args)
{
    args.IsValid = false;
    if(args.Value != "")
    {
        args.IsValid = true;
    }
}
</script>