C#怎么捕获USB转串口消息？
0
悬赏园豆：20
[待解决问题]
我现在开发的程序需要与单片机交互，笔记本电脑没有串口所以需要用到USB转串口，在网上找到过一些资料但都只能捕获到插入消息，拨出消息怎么也捕获不到，代码如下：
public const Int32 WM_DEVICE_CHANGE = 0x219;
public const Int32 DBT_DEVICEARRIVAL = 0x8000;
public const Int32 DBT_DEVICE_REMOVE_COMPLETE = 0x8004;
public const Int32 DBT_DEVTYP_PORT = 0x00000003;
[StructLayout(LayoutKind.Sequential)]
public 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 UInt32 dbcp_size;
public UInt32 dbcp_devicetype;
public UInt32 dbcp_reserved;
}
protected override void WndProc(ref Message m)
{
if (m.Msg == WM_DEVICE_CHANGE)
{
switch (m.WParam.ToInt32())
{
case DBT_DEVICEARRIVAL: //串口插入
if (!IsCopy)
{
DEV_BROADCAST_HDR dbhdr = (DEV_BROADCAST_HDR)Marshal.PtrToStructure(m.LParam, typeof(DEV_BROADCAST_HDR));
if (dbhdr.dbch_devicetype ==DBT_DEVTYP_PORT)
{
IsCopy = true;
string portName = Marshal.PtrToStringUni((IntPtr)(m.LParam.ToInt32() + Marshal.SizeOf(typeof(DEV_BROADCAST_PORT_Fixed))));
}
}
break;
case 0x8004://DBT_DEVICE_REMOVE_COMPLETE: // 串口拔出
DEV_BROADCAST_HDR dbhd = (DEV_BROADCAST_HDR)Marshal.PtrToStructure(m.LParam, typeof(DEV_BROADCAST_HDR));
if (dbhd.dbch_devicetype == DBT_DEVTYP_PORT)
{
}
break;
}
}
base.WndProc(ref m);
}
请高手帮忙指点解决下谢谢！
所有回答(2)
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USB转串口后，就是读写串口操作了，不要考虑USB了。注意购买的转接线要注意，Z-Tek这个牌子的好用，我换过好几个。
主要是下面两个方法，你查查使用。
[DllImport("kernel32.dll")]
private static extern bool ReadFile(
IntPtr hFile, // handle to file
byte[] lpBuffer, // data buffer
int nNumberOfBytesToRead, // number of bytes to read
ref int lpNumberOfBytesRead, // number of bytes read
ref OVERLAPPED lpOverlapped // overlapped buffer
);
[DllImport("kernel32.dll")]
private static extern bool WriteFile(
IntPtr hFile, // handle to file
byte[] lpBuffer, // data buffer
int nNumberOfBytesToWrite, // number of bytes to write
ref int lpNumberOfBytesWritten, // number of bytes written
ref OVERLAPPED lpOverlapped // overlapped buffer
);
[DllImport("kernel32.dll")]
private static extern bool CloseHandle(
IntPtr hFile // handle to file
);
还忘记一个打开串口的方法：
[DllImport("kernel32.dll")]
private static extern IntPtr CreateFile(
string lpFileName, // file name
uint dwDesiredAccess, // access mode
uint dwShareMode, // share mode
uint lpSecurityAttributes, // SD
uint dwCreationDisposition, // how to create
uint dwFlagsAndAttributes, // file attributes
int hTemplateFile // handle to template file
);
你这些API都是用来读写打开关闭串口的，跟检测USB消息完全没关系啊，有可以你还没有完全理解我的意思，现在什么都是使用USB，所以现在的串口也是用到USB转串口，既然是USB当然会在使用的过程会被拨出，所以我才会想到使用windows消息来检测USB转串口是否被拨出。
@为了面包: 我的意思是既然你转串口了，那就按串口的思路操作了，撇开USB驱动。通过打开串口，是否失败来判断线在不在啊，我没有测试过，不知道线拔出，串口是否打开成功。
0
直接使用SerialPort 进行串口通信不就行了
