if (_readStream != null)

                        _readStream.Dispose();

                    if (_writeStream != null)

                        _writeStream.Dispose();

                }

                //这里释放非托管资源

                //do something release unmanaged resources.

                _disposed = true;

            }

        }

        public void Dispose()

        {

            this.Dispose(true);

            GC.SuppressFinalize(this);

        }

}

public class DerivedClass:BaseClass

    {

        private FileStream _myStream;

        //如果该类没有非托管资源则注释该终结器函数，该函数的添加会从一定

        //程度上损伤程序性能。

        ~DerivedClass()

        {

            this.Dispose(false);

        }

        public void ReadNextChunk()

        {

            if (_disposed)

                throw new ObjectDisposedException("object has been disposed.");

            //do the real thing.

        }

        protected override void Dispose(bool disposing)

        {

            if (!_disposed)

            {

                try

                {

                    i