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Building Disposable Objects

As you have seen, finalizers can be used to release unmanaged resources when the garbage collec-

tor kicks in. However, given that many unmanaged objects are “precious items” (such as database or

file handles), it may be valuable to release them as soon as possible instead of relying on a garbage

collection to occur. As an alternative to overriding Finalize(), your class could implement the

IDisposable interface, which defines a single method named Dispose():

public interface IDisposable

{

void Dispose();

}

If you are new to interface-based programming, Chapter 9 will take you through the details. In

a nutshell, an interface as a collection of abstract members a class or structure may support. When

you do support the IDisposable interface, the assumption is that when the object user is finished

using the object, it manually calls Dispose() before allowing the object reference to drop out of

scope. In this way, an object can perform any necessary cleanup of unmanaged resources without

incurring the hit of being placed on the finalization queue and without waiting for the garbage col-

lector to trigger the class’s finalization logic.