Read original post by Michael Washington at LightSwitch Help Website
Visual Studio LightSwitch allows you to create Business Type extensions. A Business Type “enables you to present data in a way that is most appropriate for your application without changing the data type in which the data is stored in the underlying database”. In this article we will create a Business Type for a Customer Code. The underlying type will be a String, but the Business Type will be a custom type that requires the first character to not be a number and for it to be at least 10 characters long. It will also have its own custom control for display and editing.