http://msdn.microsoft.com/zh-tw/magazine/cc337900.aspx 其實寫了應用程式之後,發現UI真的是處處非同步啊~ 重點在這裡,有遞迴呼叫的fu: AsyncCallback rc = readResult => { int read = source.EndRead(readResult); if (read > 0) { destination.BeginWrite(buffer, 0, read, writeResult => { destination.EndWrite(writeResult); source.BeginRead(buffer, 0, buffer.Length, rc, null); } } } source.BeginRead(buffer, 0, buffer.Length, rc, null); 延伸使用: http://msdn.microsoft.com/zh-tw/magazine/cc700359.aspx