Pro C# 2010 and the .NET 4 Platform, Fifth Edition

11.9. Understanding C# Events

Delegates are fairly interesting constructs in that they enable objects in memory to engage in a two-way conversation. However, working with delegates in the raw can entail the creation of some boilerplate code (defining the delegate, declaring necessary member variables, and creating custom registration and unregistration methods to preserve encapsulation, etc.).

Moreover, when you use delegates in the raw as your application's callback mechanism, if you do not define a class's delegate member variables as private, the caller will have direct access to the delegate objects. In this case, the caller could reassign the variable to a new delegate object (effectively deleting the current list of functions to call) ...