我如何确定提交时至少点击了一个电台

Question

Does anyone know how can I make sure that they are at least one radio been click when submit in C# .net?

I have the following code:

<asp:RadioButtonList ID="billingType" runat="server" CssClass="cl_billing_method"
     RepeatDirection="Horizontal" data-messages="{required:'Billing methods is required'}">
    <asp:ListItem Text="Email" Value="1"></asp:ListItem>
    <asp:ListItem Text="Digital Mailbox" Value="2"></asp:ListItem>
    <asp:ListItem Text="Paper" Value="0"></asp:ListItem>
</asp:RadioButtonList> 

How can I validate it so that when submit button is been clicked and it will do the client check and show error if there have no radio button been selected?

Answer 1

<script type="text/javascript" language="javascript">
function Validate_Checkbox()
{
    var chks=document.getElementsByTagName('input');   
    var hasChecked = false;
    for (var i = 0; i < chks.length; i++)
    {
        if (chks[i].checked)
        {
            hasChecked = true;
            break;
        }
   }
   if (hasChecked == false)
   {
        alert("Please select at least one checkbox..!");

        return false;
   }

    return true;
}     
</script>

and on Submit Button you have to write

write

OnClientClick="return Validate_Checkbox()"

Answer 2

Better option is use a asp:RequiredFieldValidator it will looks like this:

<asp:RequiredFieldValidator ErrorMessage="Billing methods is required"
 ControlToValidate="billingType" runat="server" ValidationGroup="validateBill"  />

Add ValidationGroup to the button:

<asp:Button Text="Submit" ID="btnSubmit" runat="server" ValidationGroup="validateBill"/>

If you are getting some error saying "UnobtrusiveValidationMode requires a ScriptResourceMapping for 'jquery' ..." then add the following lines to the config:

<appSettings>
    <add key="ValidationSettings:UnobtrusiveValidationMode" value="None" />
</appSettings>