完成

Finalizers should always be protected, not public or private so that the method cannot be called from the application's code directly and at the same time, it can make a call to the base.Finalize method Finalizers should release unmanaged resources only. The framework does not guarantee that a finalizer will execute at all on any given instance. Never allocate memory in finalizers or call virtual methods from finalizers. Avoid synchronization and raising unhandled exceptions in the finalizers. The execution order of finalizers is non-deterministic—in other words, you can't rely on another object still being available within your finalizer. Do not define finalizers on value types. Don't create empty destructors. In other words, you should never explicitly define a destructor unless your class needs to clean up unmanaged resources and if you do define one, it should do some work. If, later, you no longer need to clean up unmanaged resources in the destructor, remove it altogether.

拥有

Implement IDisposable on every type that has a finalizer Ensure that an object is made unusable after making a call to the Dispose method. In other words, avoid using an object after the Dispose method has been called on it. Call Dispose on all IDisposable types once you are done with them Allow Dispose to be called multiple times without raising errors. Suppress later calls to the finalizer from within the Dispose method using the GC.SuppressFinalize method Avoid creating disposable value types Avoid throwing exceptions from within Dispose methods

处理/确定模式

Microsoft recommends that you implement both Dispose and Finalize when working with unmanaged resources. The Finalize implementation would run and the resources would still be released when the object is garbage collected even if a developer neglected to call the Dispose method explicitly. Cleanup the unmanaged resources in the Finalize method as well as Dispose method. Additionally call the Dispose method for any .NET objects that you have as components inside that class(having unmanaged resources as their member) from the Dispose method.

Finalize在该对象不再使用时由GC调用。

Dispose只是一个普通的方法，该类的用户可以调用它来释放任何资源。

如果用户忘记调用Dispose，如果类实现了Finalize，那么GC将确保它被调用。

终结器用于隐式清理——当一个类管理着绝对必须清理的资源时，你应该使用它，否则你会泄漏句柄/内存等等……

正确实现终结器是出了名的困难，应该尽可能避免——SafeHandle类(在. net v2.0及以上版本中可用)现在意味着您很少(如果有的话)需要实现终结器了。

IDisposable接口用于显式清理，并且使用得更普遍——您应该使用它来允许用户在使用完对象后显式地释放或清理资源。

注意，如果您有终结器，那么您还应该实现IDisposable接口，以允许用户显式地更快地释放这些资源，而不是在对象被垃圾收集的情况下。

请参阅DG更新:处置，终结，和资源管理，我认为是最好的和最完整的一组关于终结器和IDisposable的建议。

Class instances often encapsulate control over resources that are not managed by the runtime, such as window handles (HWND), database connections, and so on. Therefore, you should provide both an explicit and an implicit way to free those resources. Provide implicit control by implementing the protected Finalize Method on an object (destructor syntax in C# and the Managed Extensions for C++). The garbage collector calls this method at some point after there are no longer any valid references to the object. In some cases, you might want to provide programmers using an object with the ability to explicitly release these external resources before the garbage collector frees the object. If an external resource is scarce or expensive, better performance can be achieved if the programmer explicitly releases resources when they are no longer being used. To provide explicit control, implement the Dispose method provided by the IDisposable Interface. The consumer of the object should call this method when it is done using the object. Dispose can be called even if other references to the object are alive.

注意，即使通过Dispose方法提供显式控制，也应该使用Finalize方法提供隐式清理。Finalize提供了一个备份，以防止程序员在调用Dispose失败时永久地泄漏资源。

finalizer方法在对象被垃圾收集时被调用，并且您无法保证何时会发生这种情况(您可以强制执行，但这会影响性能)。

另一方面，Dispose方法应该由创建类的代码调用，以便在代码处理完对象后立即清理和释放已获得的任何资源(非托管数据、数据库连接、文件句柄等)。

标准实践是实现IDisposable和Dispose，这样就可以在using语句中使用对象。例如使用(var foo = new MyObject()){}。在终结器中，你调用Dispose，以防调用代码忘记释放你。

这是我知道的最好的例子。

 public abstract class DisposableType: IDisposable
  {
    bool disposed = false;

    ~DisposableType()
    {
      if (!disposed) 
      {
        disposed = true;
        Dispose(false);
      }
    }

    public void Dispose()
    {
      if (!disposed) 
      {
        disposed = true;
        Dispose(true);
        GC.SuppressFinalize(this);
      }
    }

    public void Close()
    {
      Dispose();
    }

    protected virtual void Dispose(bool disposing)
    {
      if (disposing) 
      {
        // managed objects
      }
      // unmanaged objects and resources
    }
  }