aspnet-validators-support.md

title	page_title	description	slug	tags	published	position
ASP.NET Validators Support	ASP.NET Validators Support | RadCheckBoxList for ASP.NET AJAX Documentation	ASP.NET Validators Support	checkboxlist/functionality/aspnet-validators-support	checkboxlist, checkbox, aspnet,validators,support, validate, validation, native	true	2

ASP.NET Validators Support

In this article you can see how to integrate native ASP.NET validation control with RadCheckBoxList.

As of R1 2017 version there is built-in support for RequiredFieldValidator control. Older versions can be integrated with the CustomValidator control as alternative solution (see Example 2).

Using RequiredFieldValidator

To use the RequiredFieldValidator you just need to set the ControlToValidate property to the CheckBoxList's ID. This will trigger validation when user submits and the validation control will validate against the SelectedItem property and return the appropriate validation result.

caption Example 1: Configuring RequiredFieldValidator control with CheckBoxList.

<telerik:RadCheckBoxList runat="server" ID="RadCheckBoxList1" AutoPostBack="false">
	<Items>
		<telerik:ButtonListItem Text="Option 1" Value="0" />
		<telerik:ButtonListItem Text="Option 2" Value="1" />
		<telerik:ButtonListItem Text="Option 3" Value="2" />
	</Items>
</telerik:RadCheckBoxList>

<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" 
    ControlToValidate="RadCheckBoxList1"
    ErrorMessage="Please choose at least one of the options displayed" />

Using CustomValidator

As an alternative to the RequiredFieldValidator you can use CustomValidator and have your own logic that validates the CheckBoxList.

caption Example 2: Configuring CustomValidator control with CheckBoxList.

<telerik:RadCheckBoxList runat="server" ID="RadCheckBoxList1" AutoPostBack="false">
	<Items>
		<telerik:ButtonListItem Text="Option 1" Value="0" />
		<telerik:ButtonListItem Text="Option 2" Value="1" />
		<telerik:ButtonListItem Text="Option 3" Value="2" />
	</Items>
</telerik:RadCheckBoxList>

<asp:CustomValidator ID="CustomButtonListValidator" runat="server" 
    ErrorMessage="Please choose at least one of the options displayed"
    OnServerValidate="CustomButtonListValidator_ServerValidate" />

protected void CustomButtonListValidator_ServerValidate(object source, ServerValidateEventArgs args)
{
    args.IsValid = (RadCheckBoxList1.SelectedIndex > -1);
}

Protected Sub CustomButtonListValidator_ServerValidate(source As Object, args As ServerValidateEventArgs)
	args.IsValid = (RadCheckBoxList1.SelectedIndex > -1)
End Sub

See Also

• [Overview]({%slug checkboxlist/overview%})

• [Getting Started]({%slug checkboxlist/getting-started%})