类型不匹配？

Question

 
           public void ReadCallback(IAsyncResult ar)
           {
            StateObject state = (StateObject)ar.AsyncState;
            Socket clientSocket = state.workSocket;
            int bytesRead = clientSocket.EndReceive(ar);
            if(bytesRead>0)
            {
                String str=Encoding.Unicode.GetBytes(state.buffer,0,bytesRead);
                textBox1.AppendText("客户端对说："+str+"\r\n");
            }
            clientSocket.BeginReceive(state.buffer,0,StateObject.BufferSize,0,new AsyncCallback(ReadCallback),state);
        }错误 1 与“System.Text.Encoding.GetBytes(char[], int, int)”最匹配的重载方法具有一些无效参数 D:\c#\pp\pp\Form1.cs 54 28 pp

Answer 1

应该是GetString吧
String str=Encoding.Unicode.GetString(state.buffer,0,bytesRead);

Answer 2

好像GetBytes()返回的是字节数组，不是字符串。