Required Field Validator for Combination of Textboxes

Question

I have three Textboxes :

1. Total Weight: <asp:TextBox runat="server" ID="TxtWt" Width="100px" ValidationGroup="AddComplexIng"></asp:TextBox>
2. Min Weight: <asp:TextBox runat="server" ID="TxtMinRnge" Width="100px" ValidationGroup="AddComplexIng"></asp:TextBox>
3. Max Weight: <asp:TextBox runat="server" ID="TxtMaxRnge" Width="100px" ValidationGroup="AddComplexIng"></asp:TextBox>

How can I use a required field validator so that following validation is achieved:

a. User enters values in all three textboxes i.e. Total Weight, Max Weight & Min Weight.

b. User enters atleast one : either user enters value for Total weight and leave min & max weight empty or user can leave Total weight empty and will have to enter both min & max weight.

Answer 1

You can use a CustomValidator.

<asp:CustomValidator ID="CustomValidator1" runat="server" ErrorMessage="Input incorrect" ClientValidationFunction="myValidator" ValidationGroup="AddComplexIng"></asp:CustomValidator>

<script type="text/javascript">
    function myValidator(oSrc, args) {
        var a = document.getElementById('<%= TxtWt.ClientID %>').value;
        var b = document.getElementById('<%= TxtMinRnge.ClientID %>').value;
        var c = document.getElementById('<%= TxtMaxRnge.ClientID %>').value;

        if (a != "" && b != "" && c != "") {
            args.IsValid = true;
        } else if (a != "" && b == "" && c == "") {
            args.IsValid = true;
        } else if (a == "" && b != "" && c != "") {
            args.IsValid = true;
        } else {
            args.IsValid = false;
        }
    }
</script>