1.用BinaryWriter寫string 的時候會在檔案開頭多出一個字元數。

2.若要從二進位制流中寫二進位制，務必別轉換成string寫byte，這樣會產生一些符號出錯。

3.網路二進位制流讀與寫程式碼：

        void Callback(IAsyncResult asyncResult)
        {

            FileInfo f = new FileInfo(@"D:\test2.mf");
         
            using (BinaryWriter bWriter = new BinaryWriter(f.OpenWrite()))
            {
                WebRequest request = asyncResult.AsyncState as WebRequest;
                WebResponse response = request.EndGetResponse(asyncResult);
                Stream responseStream = response.GetResponseStream();
                BinaryReader bReader = new BinaryReader(responseStream);
       byte[] buffer = oReader.ReadBytes(10000000);
                bw.Write(buffer);

            }

}