This example shows how Telerik DatePicker for ASP.NET MVC is using build-in client validation of the ASP.NET MVC 2.0

Validation of the Model is based on the DataAnnotations. Except, all required actions to enable build-in client validation, important thing is that the datepicker should have the same name as the validated property of the Model. In other words if DeliveryDate is a property of the Model, datepicker should be named "DeliveryDate".

Here is the definition of the DeliveryDate property, which is validated in this demo:

    [Required]
    public DateTime? DeliveryDate
    {
        get;
        set;
    }

The [Required] attribute comes from the System.ComponentModel.DataAnnotations.