Customvalidator: Check if radiobuttonlist contains a selected item - asp.net

Question

I have a radiobuttonlist with two items, Yes or No. The radiobuttonlist control has a customvalidator that needs a servervalidation function and a javascript clientvalidationfunction. Could you help me? The function in this message works but only when i actually have choosen one of the two listitems, when no listitem is selected the validation skips my radiobuttonlist control.
function ValidateRadioButtonList(source, arguments) {
var RBL = document.getElementById(source.controltovalidate);
var radiobuttonlist = RBL.getElementsByTagName("input");
var counter = 0;
var atLeast = 1
for (var i = 0; i < radiobuttonlist.length; i++) {
if (radiobuttonlist[i].checked) {
counter++;
}
}
if (atLeast = counter) {
arguments.IsValid = true;
return arguments.IsValid;
}
arguments.IsValid = false;
return arguments.IsValid;
}
EDIT: Relevant code from comments
<asp:Button ID="btnSubmit" runat="server" Text="Submit" CssClass="btnNormal"
CausesValidation="True" />
<asp:CustomValidator runat="server"
ClientValidationFunction="ValidateRadioButtonList"
OnServerValidate="RadioButtonListServerValidation" ID="cvRadioButtonList"
Font-Bold="True" Font-Size="Medium" ErrorMessage="Business critical"
ControlToValidate="rblBusinessCritical">*</asp:CustomValidator>
<asp:RadioButtonList ID="rblBusinessCritical" runat="server" RepeatLayout="Flow"
RepeatDirection="Horizontal" TabIndex="4">
<asp:ListItem Text="Yes" Value="1" />
<asp:ListItem Text="No" Value="0" />
</asp:RadioButtonList>
Code Behind:
Public Sub RadioButtonListServerValidation(ByVal sender As Object, _
ByVal args As ServerValidateEventArgs)
If rblBusinessCritical.SelectedValue = "-1" Then
args.IsValid = False
cvRadioButtonList.ErrorMessage = "Business critical needed"
Exit Sub
Else
args.IsValid = True
End If
End Sub

Answer 1

Have you set the ValidateEmptyText Property of the CustomValidator to true?
edit:
Have you set the CausesValidation Property of your Submit-Button/RadioButtonList to true?
Please provide some code from your aspx-page.

Answer 2

Here is another javascript clientvalidation function i have tried:
function ValidateRadioButtonList(source, arguments) {
var RBL = document.getElementById(source.controltovalidate);
var radio = RBL.getElementsByTagName("input");
var isChecked = false;
for (var i = 0; i < radio.length; i++) {
if (radio[i].checked) {
isChecked = true;
break;
}
}
if (!isChecked) {
alert("Please select an item");
arguments.IsValid = false;
}
arguments.IsValid = true;
}

Answer 3

Do you need to use client-side?
Here is a server-side solution...
<asp:RadioButtonList id="radTerms" runat="server">
<asp:listitem id="optDisagree" runat="server" value="Disagree" selected="true">I don't agree</asp:ListItem>
<asp:listitem id="optAgree" runat="server" value="Agree">I agree</asp:ListItem>
</asp:RadioButtonList>
<asp:CustomValidator Display="Dynamic" ErrorMessage="You have to agree to the terms and conditions" ID="cmpTerms" ControlToValidate="radTerms" SetFocusOnError="true" runat="server" OnServerValidate="cmpTermsAccepted_ServerValidate">*</asp:CustomValidator>
CodeBehind:
protected void cmpTermsAccepted_ServerValidate(Object source, System.Web.UI.WebControls.ServerValidateEventArgs args)
{
args.IsValid = (args.Value == "Agree");
}

Answer 4

That should work. Trying taking the control to validate property off the customer validator.

Answer 5

<asp:RadioButtonList ID="LocationAccurateRBL" CssClass="radioButtonList" RepeatDirection="Horizontal" RepeatColumns="4" RepeatLayout="Flow" runat="server">
<asp:ListItem Text="Yes" Value="1" />
<asp:ListItem Text="No" Value="0" />
</asp:RadioButtonList>
<asp:CustomValidator runat="server" ID="CheckBoxRequired" EnableClientScript="true" ControlToValidate="LocationAccurateRBL"
ClientValidationFunction="LocationAccurate_ClientValidate" ValidateEmptyText="true"
Text="*" ForeColor="Red" ErrorMessage="Please let us know if the location is accurate" SetFocusOnError="true" ValidationGroup="CreateVG" />
And the script, is much shorter because of jquery. This will do what you want.
<script>
function LocationAccurate_ClientValidate(sender, e) {
e.IsValid = $("#<%=LocationAccurateRBL.ClientID%> > input").is(':checked');
}
</script>