C#中USB转串口的拔插捕获

2012-11-28 23:15:44|??分类：?项目心得?|??标签：c#??usb转串口??|举报|字号?订阅

C#中USB转串口的拔插捕获

最近一个C#项目用户要求能够实现插入USB接口，自动识别所接入的串口，而无需人工去选择插入的是那个串口。通过一阵子的资料搜罗，总算找到一个最佳的实现方案。以前是通过线程循环逐个打开串口，发送握手包来确认接入的是那个串口，这么做能实现，不过会产生通信的数据包信息。现在，采用windows的消息机制来捕获插入的usb状态，然后，获取对应的串口名称。代码如下:

??????? [StructLayout(LayoutKind.Sequential)]
??????? struct DEV_BROADCAST_HDR
??????? {
??????????? public UInt32 dbch_size;
??????????? public UInt32 dbch_devicetype;
??????????? public UInt32 dbch_reserved;
??????? }

?????? ?[StructLayout(LayoutKind.Sequential)]????????
??????? protected struct DEV_BROADCAST_PORT_Fixed
??????? {
??????????? public uint dbcp_size;
??????????? public uint dbcp_devicetype;
??????????? public uint dbcp_reserved;
??????????? // Variable?length field dbcp_name is declared here in the C header file.
??????? }

??????? /// <summary>
??????? /// 检测USB串口的拔插
??????? /// </summary>
??????? /// <param name="m"></param>
??????? protected override void WndProc(ref Message m)
??????? {
??????????? if (m.Msg == WM_DEVICE_CHANGE)??????? // 捕获USB设备的拔出消息WM_DEVICECHANGE
??????????? {
????????????????switch (m.WParam.ToInt32())
??????????????? {
???????????????????case DBT_DEVICE_REMOVE_COMPLETE:??? // USB拔出????????????????????????
????????????????????????????break;
??????????????????? case DBT_DEVICEARRIVAL:???????????? // USB插入获取对应串口名称
??????????????????????????? DEV_BROADCAST_HDR dbhdr = (DEV_BROADCAST_HDR)Marshal.PtrToStructure(m.LParam,typeof(DEV_BROADCAST_HDR));
??????????????????????? if (dbhdr.dbch_devicetype == DBT_DEVTYP_PORT)? {
??????????????????????????? string portName = Marshal.PtrToStringUni((IntPtr)(m.LParam.ToInt32() +Marshal.SizeOf(typeof(DEV_BROADCAST_PORT_Fixed))));
??????????????????????????? Console.WriteLine("Port '" + portName + "' arrived.");
??????????????????????? }????????????????????????
??????????????????? break;
??????????????? }????????????????
??????????? }
??????????? base.WndProc(ref m);
??????? }

（编辑：北几岛）

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