SocketAsyncEventArgs.SetBuffer

设置要用于异步套接字方法的数据缓冲区。

public void SetBuffer(byte[] buffer,int offset,int count)

buffer:要用于异步套接字方法的数据缓冲区，类型为Byte[]。

offset:数据缓冲区中操作开始位置处的偏移量，以字节为单位，类型为Int32。

count:可在缓冲区中发送或接收的最大数据量（以字节为单位），类型为Int32。

注意：offset 和 count 参数不能为负数。offset 和 count 参数的组合必须在 buffer 参数中的数据数组的界限内。

// This class creates a single large buffer which can be divided up // and assigned to SocketAsyncEventArgs objects for use with each // socket I/O operation. // This enables bufffers to be easily reused and guards against // fragmenting heap memory.// // The operations exposed on the BufferManager class are not thread safe.class BufferManager{ int m_numBytes; // the total number of bytes controlled by the buffer pool byte[] m_buffer; // the underlying byte array maintained by the Buffer Manager Stack<int> m_freeIndexPool; // int m_currentIndex; int m_bufferSize; public BufferManager(int totalBytes, int bufferSize) { m_numBytes = totalBytes; m_currentIndex = 0; m_bufferSize = bufferSize; m_freeIndexPool = new Stack<int>(); } // Allocates buffer space used by the buffer pool public void InitBuffer() { // create one big large buffer and divide that // out to each SocketAsyncEventArg object m_buffer = new byte[m_numBytes]; } // Assigns a buffer from the buffer pool to the // specified SocketAsyncEventArgs object // // <returns>true if the buffer was successfully set, else false</returns> public bool SetBuffer(SocketAsyncEventArgs args) { if (m_freeIndexPool.Count > 0) { args.SetBuffer(m_buffer, m_freeIndexPool.Pop(), m_bufferSize); } else { if ((m_numBytes - m_bufferSize) < m_currentIndex) { return false; } args.SetBuffer(m_buffer, m_currentIndex, m_bufferSize); m_currentIndex += m_bufferSize; } return true; } // Removes the buffer from a SocketAsyncEventArg object. // This frees the buffer back to the buffer pool public void FreeBuffer(SocketAsyncEventArgs args) { m_freeIndexPool.Push(args.Offset); args.SetBuffer(null, 0, 0); }}