I have a web form using asp controls.
I am implementing validation into the form.
I've run into a little snag I can't seem to get past.

Here's the code:

<asp:RadioButton ID="CC" Text="Credit Card" GroupName="PayMethod" runat="server" />
<asp:RadioButton ID="Check" Text="Check/Money Order" GroupName="PayMethod" runat="server" />

<asp:DropDownList ID="CardType" runat="server">
     <asp:ListItem Value="" Selected="true"></asp:ListItem>
     <asp:ListItem Value="Visa">Visa</asp:ListItem>
     <asp:ListItem Value="MC">MasterCard</asp:ListItem>
     <asp:ListItem Value="Amex">American Express</asp:ListItem>
     <asp:ListItem Value="Disc">Discover</asp:ListItem>
</asp:DropDownList>

What I want is if the Credit Card radiobutton is selected then the CardType dropdown must be validated. If the Check/Money Order radiobutton is selected, the dropdown will remain blank and I don't want to validate it.

I tried this right below the dropdown list:

<% If CC.checked = "True" then %>
     <asp:RequiredFieldValidator ID="CardTypeRequired" ControlToValidate="CardType" runat="server" ErrorMessage="Credit Card Type">***</asp:RequiredFieldValidator>
<% End If %>

But the Validator runs whether CC.checked is true or false.
Not sure how to put the IF-THEN where it will work.
Any help is appreciated.
Thanks

-Tom

This works fine for me...

<form id="Form1" method="post" runat="server">
		<asp:RadioButton ID="CC" Text="Credit Card" GroupName="PayMethod" runat="server" />
		<asp:RadioButton ID="Check" Text="Check/Money Order" GroupName="PayMethod" runat="server" />
		<asp:DropDownList ID="CardType" runat="server">
			<asp:ListItem Value="" Selected="true"></asp:ListItem>
			<asp:ListItem Value="Visa">Visa</asp:ListItem>
			<asp:ListItem Value="MC">MasterCard</asp:ListItem>
			<asp:ListItem Value="Amex">American Express</asp:ListItem>
			<asp:ListItem Value="Disc">Discover</asp:ListItem>
		</asp:DropDownList>
		<% If CC.checked = "True" then %>
			<asp:RequiredFieldValidator ID="CardTypeRequired" ControlToValidate="CardType" runat="server" ErrorMessage="Credit Card Type">***</asp:RequiredFieldValidator>
		<% End If %>
		<br>
		<INPUT type="submit" value="Submit">
</form>

Instead of having code in the body of your document, you could use:

<asp:CustomValidator id="cvCCard" runat="server" ControlToValidate="CardType" ErrorMessage="Credit Card Type" OnServerValidate="cvCard_Validate">***</asp:CustomValidator>

Then in the <script> tags,

Sub cvCCard_Validate(source As Object, args As ServerValidateEventArgs)
    If CC.Checked Then
        If args.Value = String.Empty Then args.IsValid = False Else IsValid = True
    End If
End Sub

There is a nice Creditcard validator at ASPEmporium.com
Try there.

Hope that helps.