来自msdn的模式

public class BaseResource: IDisposable
{
   private IntPtr handle;
   private Component Components;
   private bool disposed = false;
   public BaseResource()
   {
   }
   public void Dispose()
   {
      Dispose(true);      
      GC.SuppressFinalize(this);
   }
   protected virtual void Dispose(bool disposing)
   {
      if(!this.disposed)
      {        
         if(disposing)
         {
            Components.Dispose();
         }         
         CloseHandle(handle);
         handle = IntPtr.Zero;
       }
      disposed = true;         
   }
   ~BaseResource()      
   {      Dispose(false);
   }
   public void DoSomething()
   {
      if(this.disposed)
      {
         throw new ObjectDisposedException();
      }
   }
}
public class MyResourceWrapper: BaseResource
{
   private ManagedResource addedManaged;
   private NativeResource addedNative;
   private bool disposed = false;
   public MyResourceWrapper()
   {
   }
   protected override void Dispose(bool disposing)
   {
      if(!this.disposed)
      {
         try
         {
            if(disposing)
            {             
               addedManaged.Dispose();         
            }
            CloseHandle(addedNative);
            this.disposed = true;
         }
         finally
         {
            base.Dispose(disposing);
         }
      }
   }
}

另一个答案的某些方面有点不正确，原因有二:

首先,

using(NoGateway objNoGateway = new NoGateway())

Actually相当于:

try
{
    NoGateway = new NoGateway();
}
finally
{
    if(NoGateway != null)
    {
        NoGateway.Dispose();
    }
}

This may sound ridiculous since the 'new' operator should never return 'null' unless you have an OutOfMemory exception. But consider the following cases: 1. You call a FactoryClass that returns an IDisposable resource or 2. If you have a type that may or may not inherit from IDisposable depending on its implementation - remember that I've seen the IDisposable pattern implemented incorrectly many times at many clients where developers just add a Dispose() method without inheriting from IDisposable (bad, bad, bad). You could also have the case of an IDisposable resource being returned from a property or method (again bad, bad, bad - don't 'give away your IDisposable resources)

using(IDisposable objNoGateway = new NoGateway() as IDisposable)
{
    if (NoGateway != null)
    {
        ...

如果'as'操作符返回null(或返回资源的属性或方法)，并且'using'块中的代码可以防止'null'，那么在尝试对空对象调用Dispose时，您的代码不会因为'内置'空检查而崩溃。

你的回复不准确的第二个原因是由于以下stmt:

在GC销毁对象时调用终结器

First, Finalization (as well as GC itself) is non-deterministic. THe CLR determines when it will call a finalizer. i.e. the developer/code has no idea. If the IDisposable pattern is implemented correctly (as I've posted above) and GC.SuppressFinalize() has been called, the the Finalizer will NOT be called. This is one of the big reasons to properly implement the pattern correctly. Since there is only 1 Finalizer thread per managed process, regardless of the number of logical processors, you can easily degrade performance by backing up or even hanging the Finalizer thread by forgetting to call GC.SuppressFinalize().

我已经在我的博客上发布了Dispose模式的正确实现:如何正确地实现Dispose模式

我同意pm100的观点(我应该在之前的文章中明确地说明这一点)。

除非需要，否则永远不要在类中实现IDisposable。具体来说，大约有5次你需要/应该实现IDisposable:

Your class explicitly contains (i.e. not via inheritance) any managed resources which implement IDisposable and should be cleaned up once your class is no longer used. For example, if your class contains an instance of a Stream, DbCommand, DataTable, etc. Your class explicitly contains any managed resources which implement a Close() method - e.g. IDataReader, IDbConnection, etc. Note that some of these classes do implement IDisposable by having Dispose() as well as a Close() method. Your class explicitly contains an unmanaged resource - e.g. a COM object, pointers (yes, you can use pointers in managed C# but they must be declared in 'unsafe' blocks, etc. In the case of unmanaged resources, you should also make sure to call System.Runtime.InteropServices.Marshal.ReleaseComObject() on the RCW. Even though the RCW is, in theory, a managed wrapper, there is still reference counting going on under the covers. If your class subscribes to events using strong references. You need to unregister/detach yourself from the events. Always to make sure these are not null first before trying to unregister/detach them!. Your class contains any combination of the above...

对于使用COM对象并且必须使用Marshal.ReleaseComObject()，推荐的替代方法是使用System.Runtime.InteropServices.SafeHandle类。

BCL(基类库团队)在这里有一篇关于它的很好的博客文章http://blogs.msdn.com/bclteam/archive/2005/03/16/396900.aspx

一个非常重要的注意事项是，如果你正在使用WCF并清理资源，你几乎总是应该避免使用'using'块。有很多博客和MSDN上的文章都在解释为什么这是一个坏主意。我也在这里发布了关于它的帖子-不要在WCF代理中使用'using()'

Note that any IDisposable implementation should follow the below pattern (IMHO). I developed this pattern based on info from several excellent .NET "gods" the .NET Framework Design Guidelines (note that MSDN does not follow this for some reason!). The .NET Framework Design Guidelines were written by Krzysztof Cwalina (CLR Architect at the time) and Brad Abrams (I believe the CLR Program Manager at the time) and Bill Wagner ([Effective C#] and [More Effective C#] (just take a look for these on Amazon.com:

Note that you should NEVER implement a Finalizer unless your class directly contains (not inherits) UNmanaged resources. Once you implement a Finalizer in a class, even if it is never called, it is guaranteed to live for an extra collection. It is automatically placed on the Finalization Queue (which runs on a single thread). Also, one very important note...all code executed within a Finalizer (should you need to implement one) MUST be thread-safe AND exception-safe! BAD things will happen otherwise...(i.e. undetermined behavior and in the case of an exception, a fatal unrecoverable application crash).

我把模式放在一起(并为其编写了代码片段)如下:

#region IDisposable implementation

//TODO remember to make this class inherit from IDisposable -> $className$ : IDisposable

// Default initialization for a bool is 'false'
private bool IsDisposed { get; set; }

/// <summary>
/// Implementation of Dispose according to .NET Framework Design Guidelines.
/// </summary>
/// <remarks>Do not make this method virtual.
/// A derived class should not be able to override this method.
/// </remarks>
public void Dispose()
{
    Dispose( true );

    // This object will be cleaned up by the Dispose method.
    // Therefore, you should call GC.SupressFinalize to
    // take this object off the finalization queue 
    // and prevent finalization code for this object
    // from executing a second time.

    // Always use SuppressFinalize() in case a subclass
    // of this type implements a finalizer.
    GC.SuppressFinalize( this );
}

/// <summary>
/// Overloaded Implementation of Dispose.
/// </summary>
/// <param name="isDisposing"></param>
/// <remarks>
/// <para><list type="bulleted">Dispose(bool isDisposing) executes in two distinct scenarios.
/// <item>If <paramref name="isDisposing"/> equals true, the method has been called directly
/// or indirectly by a user's code. Managed and unmanaged resources
/// can be disposed.</item>
/// <item>If <paramref name="isDisposing"/> equals false, the method has been called by the 
/// runtime from inside the finalizer and you should not reference 
/// other objects. Only unmanaged resources can be disposed.</item></list></para>
/// </remarks>
protected virtual void Dispose( bool isDisposing )
{
    // TODO If you need thread safety, use a lock around these 
    // operations, as well as in your methods that use the resource.
    try
    {
        if( !this.IsDisposed )
        {
            if( isDisposing )
            {
                // TODO Release all managed resources here

                $end$
            }

            // TODO Release all unmanaged resources here



            // TODO explicitly set root references to null to expressly tell the GarbageCollector
            // that the resources have been disposed of and its ok to release the memory allocated for them.


        }
    }
    finally
    {
        // explicitly call the base class Dispose implementation
        base.Dispose( isDisposing );

        this.IsDisposed = true;
    }
}

//TODO Uncomment this code if this class will contain members which are UNmanaged
// 
///// <summary>Finalizer for $className$</summary>
///// <remarks>This finalizer will run only if the Dispose method does not get called.
///// It gives your base class the opportunity to finalize.
///// DO NOT provide finalizers in types derived from this class.
///// All code executed within a Finalizer MUST be thread-safe!</remarks>
//  ~$className$()
//  {
//     Dispose( false );
//  }
#endregion IDisposable implementation

下面是在派生类中实现IDisposable的代码。注意，您不需要在派生类的定义中显式地列出来自IDisposable的继承。

public DerivedClass : BaseClass, IDisposable (remove the IDisposable because it is inherited from BaseClass)


protected override void Dispose( bool isDisposing )
{
    try
    {
        if ( !this.IsDisposed )
        {
            if ( isDisposing )
            {
                // Release all managed resources here

            }
        }
    }
    finally
    {
        // explicitly call the base class Dispose implementation
        base.Dispose( isDisposing );
    }
}

我已经在我的博客上发布了这个实现:如何正确地实现Dispose模式

处理模式:

public abstract class DisposableObject : IDisposable
{
    public bool Disposed { get; private set;}      

    public void Dispose()
    {
        Dispose(true);
        GC.SuppressFinalize(this);
    }

    ~DisposableObject()
    {
        Dispose(false);
    }

    private void Dispose(bool disposing)
    {
        if (!Disposed)
        {
            if (disposing)
            {
                DisposeManagedResources();
            }

            DisposeUnmanagedResources();
            Disposed = true;
        }
    }

    protected virtual void DisposeManagedResources() { }
    protected virtual void DisposeUnmanagedResources() { }
}

继承的例子:

public class A : DisposableObject
{
    public Component components_a { get; set; }
    private IntPtr handle_a;

    protected override void DisposeManagedResources()
    {
        try
        {
          Console.WriteLine("A_DisposeManagedResources");
          components_a.Dispose();
          components_a = null;
        }
        finally
        { 
          base.DisposeManagedResources();
        }
    }

    protected override void DisposeUnmanagedResources()
    {
        try
        {
          Console.WriteLine("A_DisposeUnmanagedResources");
          CloseHandle(handle_a);
          handle_a = IntPtr.Zero;
        }
        finally
        { 
          base.DisposeUnmanagedResources();
        }
    }
}

public class B : A
{
    public Component components_b { get; set; }
    private IntPtr handle_b;

    protected override void DisposeManagedResources()
    {
        try
        {
          Console.WriteLine("B_DisposeManagedResources");
          components_b.Dispose();
          components_b = null;
        }
        finally
        { 
          base.DisposeManagedResources();
        }
    }

    protected override void DisposeUnmanagedResources()
    {
        try
        {
          Console.WriteLine("B_DisposeUnmanagedResources");
          CloseHandle(handle_b);
          handle_b = IntPtr.Zero;
        }
        finally
        { 
          base.DisposeUnmanagedResources();
        }
    }
}

来自msdn的模式

public class BaseResource: IDisposable
{
   private IntPtr handle;
   private Component Components;
   private bool disposed = false;
   public BaseResource()
   {
   }
   public void Dispose()
   {
      Dispose(true);      
      GC.SuppressFinalize(this);
   }
   protected virtual void Dispose(bool disposing)
   {
      if(!this.disposed)
      {        
         if(disposing)
         {
            Components.Dispose();
         }         
         CloseHandle(handle);
         handle = IntPtr.Zero;
       }
      disposed = true;         
   }
   ~BaseResource()      
   {      Dispose(false);
   }
   public void DoSomething()
   {
      if(this.disposed)
      {
         throw new ObjectDisposedException();
      }
   }
}
public class MyResourceWrapper: BaseResource
{
   private ManagedResource addedManaged;
   private NativeResource addedNative;
   private bool disposed = false;
   public MyResourceWrapper()
   {
   }
   protected override void Dispose(bool disposing)
   {
      if(!this.disposed)
      {
         try
         {
            if(disposing)
            {             
               addedManaged.Dispose();         
            }
            CloseHandle(addedNative);
            this.disposed = true;
         }
         finally
         {
            base.Dispose(disposing);
         }
      }
   }
}