Microsoft Visual Studio 2015 Unleashed, Third Edition

Add Business Logic to Generated Code (Partial Methods)

A partial method (like a partial class) represents code you write to be added as a specific method to a given class upon compilation. This enables the author of a partial class to define an empty method stub and then call that method from other places within the class. If you provide implementation code for the partial method stub, your code is called when the stub would be called (actually the compiler merges your code with the partial class into a single class). If you do not provide a partial method implementation, the compiler goes a step further and removes the method from the class along with all calls to it. This is why such as partial method returns void and cannot take out parameters. ...