为什么bytes.length = 0？

Question

我不知道如何调试。我试图将文件上传到我的数据库中（通过将二进制文件内容读入我的存储过程）。我传递的输入流，以我的方法，像这样：

LoadFile(gAttachmentContentID, file.InputStream, trn); 

这是我的方法：

public static void LoadFile(Guid gAttachmentContentID, Stream stm, IDbTransaction trn) 
      { 
       const int BUFFER_LENGTH = 40 * 1024; 
       byte[] binFILE_POINTER = new byte[32]; 
       //Testing check out check in 
       // 01/20/2006 Paul. Must include in transaction 
       SqlProcs.spATTACHMENTS_CONTENT_InitPointer(gAttachmentContentID, ref binFILE_POINTER, trn); 

       using (BinaryReader reader = new BinaryReader(stm)) 
       { 
        int nFILE_OFFSET = 0; 
        byte[] binBYTES = reader.ReadBytes(BUFFER_LENGTH); 
        Debug.Print("binBYTES=" + binBYTES.Length.ToString()); 
        while (binBYTES.Length > 0) 
        { 
         // 08/14/2005 Paul. gID is used by Oracle, binFILE_POINTER is used by SQL Server. 
         // 01/20/2006 Paul. Must include in transaction 
         SqlProcs.spATTACHMENTS_CONTENT_WriteOffset(gAttachmentContentID, binFILE_POINTER, nFILE_OFFSET, binBYTES, trn); 
         nFILE_OFFSET += binBYTES.Length; 
         binBYTES = reader.ReadBytes(BUFFER_LENGTH); 
        } 
       } 
      } 

为什么binBYTES.length = 0？我怎样才能调试这种类型的东西？

编辑：

我现在用这个函数：

public static void LoadFile2(Guid gAttachmentContentID, Stream stm, IDbTransaction trn) 
    { 

     stm.Position = 0; 
     byte[] binFILE_POINTER = new byte[32]; 

     // Now read s into a byte buffer. 
     byte[] bytes = new byte[stm.Length]; 
     int numBytesToRead = (int)stm.Length; 
     int numBytesRead = 0; 
     while (numBytesToRead > 0) 
     { 
      // Read may return anything from 0 to 10. 
      int n = stm.Read(bytes, numBytesRead, 10); 
      // The end of the file is reached. 
      if (n == 0) 
      { 
       break; 
      } 
      numBytesRead += n; 
      numBytesToRead -= n; 



     } 
     stm.Close(); 
     SqlProcs.spATTACHMENTS_CONTENT_WriteOffset(gAttachmentContentID, binFILE_POINTER, 0, bytes, trn); 
     // numBytesToRead should be 0 now, and numBytesRead should 
     // equal 100. 
     Console.WriteLine("number of bytes read: {0:d}", numBytesRead); 

    } 

有了这个过程：

public static void spATTACHMENTS_CONTENT_WriteOffset(Guid gID, byte[] binFILE_POINTER, Int32 nFILE_OFFSET, byte[] byBYTES, IDbTransaction trn) 
     { 
      IDbConnection con = trn.Connection; 
      using (IDbCommand cmd = con.CreateCommand()) 
      { 
       cmd.Transaction = trn; 
       cmd.CommandType = CommandType.StoredProcedure; 
       if (Sql.IsOracle(cmd)) 
        cmd.CommandText = "spATTACHMENTS_CONTENT_WriteOff"; 
       else 
        cmd.CommandText = "spATTACHMENTS_CONTENT_WriteOffset"; 
       IDbDataParameter parID    = Sql.AddParameter(cmd, "@ID"    , gID    ); 
       IDbDataParameter parFILE_POINTER  = Sql.AddParameter(cmd, "@FILE_POINTER" , binFILE_POINTER ); 
       IDbDataParameter parMODIFIED_USER_ID = Sql.AddParameter(cmd, "@MODIFIED_USER_ID", Security.USER_ID ); 
       IDbDataParameter parFILE_OFFSET  = Sql.AddParameter(cmd, "@FILE_OFFSET"  , nFILE_OFFSET  ); 
       IDbDataParameter parBYTES   = Sql.AddParameter(cmd, "@BYTES"   , byBYTES   ); 
       cmd.ExecuteNonQuery(); 
      } 
     } 

，但我得到了以下错误：

Invalid text, ntext, or image pointer value 0x00000000000000000000000000000000. 

谢谢。

Answer 1

我加入这个代码，它现在工作得很好：

的IDbConnection CON = trn.Connection;使用（IDbCommand cmd = con.CreateCommand（）） { cmd.Transaction = trn;

  cmd.CommandText = "UPDATE ATTACHMENTS_CONTENT SET ATTACHMENT = @BYTES Where ID=@ID"; 

      // 2. define parameters used in command object 
      SqlParameter param = new SqlParameter(); 
      param.ParameterName = "@BYTES"; 
      param.Value = bytes; 
      cmd.Parameters.Add(param); 

      // 2. define parameters used in command object 
      SqlParameter param2 = new SqlParameter(); 
      param2.ParameterName = "@ID"; 
      param2.Value = gAttachmentContentID; 
      cmd.Parameters.Add(param2); 

      cmd.ExecuteNonQuery(); 
     } 

Answer 2

它表明你已经到达了流的末尾。从documentation：

The end of the file that is being read is detected when the length of the Byte array returned from ReadBytes is zero.

个人而言，我只是不会在这里营造出BinaryReader都：我想创建一个单字节数组，你可以重复使用，并调用Stream.Read反复（和数据复制出来），直到返回0表明它已到达流的末尾。