System.IO.MemoryStream的stream.Position = 0

//怎麼讀也讀不出來的代碼

 public override object Execute(object parameter)
        {
            using (System.IO.MemoryStream stream = parameter as System.IO.MemoryStream)
            {
                using (System.IO.BinaryWriter writer = new System.IO.BinaryWriter(System.IO.File.OpenWrite(File)))
                {
                    byte[] BUFFER = new byte[stream.Length];
                    stream.Read(BUFFER, 0, (int)stream.Length);
                    stream.Flush();
                    writer.Write(BUFFER, 0, (int)stream.Length);
                    writer.Flush();
                    stream.Close();
                    writer.Close();                    
                }
            }
            return null;
        }

//運行正常的代碼

 public override object Execute(object parameter)
        {
            using (System.IO.MemoryStream stream = parameter as System.IO.MemoryStream)
            {
                using (System.IO.BinaryWriter writer = new System.IO.BinaryWriter(System.IO.File.OpenWrite(File)))
                {
                    stream.Position = 0;
                    byte[] BUFFER = new byte[stream.Length];
                    stream.Read(BUFFER, 0, (int)stream.Length);
                    stream.Flush();
                    writer.Write(BUFFER, 0, (int)stream.Length);
                    writer.Flush();
                    stream.Close();
                    writer.Close();                    
                }
            }
            return null;
        }

//stream.Position = 0;耽誤了我的4個小時