Programming Visual Basic 2005

Encapsulating Data with Properties

It is generally desirable to designate the member variables of a class as Private. This means that only member methods of that class can access their value. You make member variables Private to support data hiding.Data hiding is part of the encapsulation of a class, and allows you to change how you store your data without breaking other classes that interact with your class.

Finalize

If you do control an unmanaged resource, it is best to explicitly free that resource as soon as you are done with it. Implicit control over this resource is provided with a finalize method, which will be called by the garbage collector when your object is destroyed.

  Protected Overrides Sub Finalize()
    ' release non-managed resources
    MyBase.Finalize()
  End Sub

It is not legal to call finalize explicitly. Finalize will be called by the garbage collector. If you do handle precious unmanaged resources (such as file handles) that you want to close and dispose of as quickly as possible, you ought to implement the IDisposable interface. (You will learn more about interfaces later in this chapter.)

The IDisposable interface requires you to create a method named Dispose which will be called by your clients.

If you provide a Dispose method, you should stop the garbage collector from calling your object's destructor. To stop the garbage collector, you call the Shared method GC.SuppressFinalize, passing in the Me reference for your object. Your Finalize method can then call your