This example shows how Telerik ComboBox 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 combobox should have the same name as the validated property of the Model. In other words if ProductID is a property of the Model, combobox should be named "ProductID".

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

        [Required]
        public int ProductID
        {
            get;
            set;
        }

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