internal string CheckDeviceChangeMessageSenderIsTargetDeviceOrNot(IntPtr LParam)
{
try
{
NativeMethods.DEV_BROADCAST_DEVICEINTERFACE devBroadcastDeviceInterface = new NativeMethods.DEV_BROADCAST_DEVICEINTERFACE();
NativeMethods.DEV_BROADCAST_HDR devBroadcastHdr = (NativeMethods.DEV_BROADCAST_HDR)Marshal.PtrToStructure(LParam, typeof(NativeMethods.DEV_BROADCAST_HDR));
if (devBroadcastHdr.dbch_devicetype == NativeMethods.DeviceType.DBT_DEVTYP_DEVICEINTERFACE)
{
// The dbch_devicetype parameter indicates that the event applies to a device interface.
// So the structure in LParam is actually a DEV_BROADCAST_INTERFACE structure,
// which begins with a DEV_BROADCAST_HDR.
// Obtain the number of characters in dbch_name by subtracting the 32 bytes
// in the structure that are not part of dbch_name and dividing by 2 because there are
// 2 bytes per character.
int stringSize = System.Convert.ToInt32((devBroadcastHdr.dbch_size - 32) / 2);
// The dbcc_name parameter of broadcastDeviceInterface contains the device name.
// Trim dbcc_name to match the size of the string.
devBroadcastDeviceInterface.dbcc_name = new string(new char[stringSize + 1]);
// Marshal data from the unmanaged block pointed to by m.LParam
// to the managed object broadcastDeviceInterface.
devBroadcastDeviceInterface = (NativeMethods.DEV_BROADCAST_DEVICEINTERFACE)Marshal.PtrToStructure(LParam, typeof(NativeMethods.DEV_BROADCAST_DEVICEINTERFACE));
return(devBroadcastDeviceInterface.dbcc_name);
}
}
catch (Exception ex)
{
Debug.WriteLine(ex.Message);
throw;
}
return(string.Empty);
}
/// <summary>
/// Worker function for WM_DEVICECHANGE messages. Invokes DeviceChangedMsg event.
/// </summary>
/// <param name="msg">Native Windows message - WM_DEVICECHANGE</param>
private void OnDeviceChange(Message msg)
{
DeviceChangeEvent devEvent = DeviceChangeEvent.Unknown;
String devDetails = String.Empty;
if (msg.LParam != IntPtr.Zero)
{
NativeMethods.DEV_BROADCAST_HDR db = (NativeMethods.DEV_BROADCAST_HDR)Marshal.PtrToStructure(msg.LParam, typeof(NativeMethods.DEV_BROADCAST_HDR));
switch (msg.WParam.ToInt32())
{
case NativeMethods.DBT_DEVICEARRIVAL:
if (db.dbch_devicetype == NativeMethods.DBT_DEVTYP.DEVICEINTERFACE)
{
NativeMethods.DEV_BROADCAST_DEVICEINTERFACE dbdi = (NativeMethods.DEV_BROADCAST_DEVICEINTERFACE)Marshal.PtrToStructure(msg.LParam, typeof(NativeMethods.DEV_BROADCAST_DEVICEINTERFACE));
if (dbdi.dbcc_classguid == NativeMethods.GUID_DEVINTERFACE_USB_DEVICE)
{
devEvent = DeviceChangeEvent.DeviceArrival;
devDetails = dbdi.dbcc_name;
}
else if (dbdi.dbcc_classguid == NativeMethods.GUID_DEVINTERFACE_USB_HUB)
{
devEvent = DeviceChangeEvent.HubArrival;
devDetails = dbdi.dbcc_name;
}
}
else if (db.dbch_devicetype == NativeMethods.DBT_DEVTYP.VOLUME)
{
NativeMethods.DEV_BROADCAST_VOLUME dbv = (NativeMethods.DEV_BROADCAST_VOLUME)Marshal.PtrToStructure(msg.LParam, typeof(NativeMethods.DEV_BROADCAST_VOLUME));
devEvent = DeviceChangeEvent.VolumeArrival;
devDetails = DrivesFromMask(dbv.dbcv_unitmask);
}
else if (db.dbch_devicetype == NativeMethods.DBT_DEVTYP.PORT)
{
NativeMethods.DEV_BROADCAST_PORT dbp = (NativeMethods.DEV_BROADCAST_PORT)Marshal.PtrToStructure(msg.LParam, typeof(NativeMethods.DEV_BROADCAST_PORT));
devEvent = DeviceChangeEvent.PortArrival;
devDetails = dbp.dbcp_name;
}
break;
case NativeMethods.DBT_DEVICEREMOVECOMPLETE:
if (db.dbch_devicetype == NativeMethods.DBT_DEVTYP.DEVICEINTERFACE)
{
NativeMethods.DEV_BROADCAST_DEVICEINTERFACE dbdi = (NativeMethods.DEV_BROADCAST_DEVICEINTERFACE)Marshal.PtrToStructure(msg.LParam, typeof(NativeMethods.DEV_BROADCAST_DEVICEINTERFACE));
if (dbdi.dbcc_classguid == NativeMethods.GUID_DEVINTERFACE_USB_DEVICE)
{
devEvent = DeviceChangeEvent.DeviceRemoval;
devDetails = dbdi.dbcc_name;
}
else if (dbdi.dbcc_classguid == NativeMethods.GUID_DEVINTERFACE_USB_HUB)
{
devEvent = DeviceChangeEvent.HubRemoval;
devDetails = dbdi.dbcc_name;
}
}
else if (db.dbch_devicetype == NativeMethods.DBT_DEVTYP.VOLUME)
{
NativeMethods.DEV_BROADCAST_VOLUME dbv = (NativeMethods.DEV_BROADCAST_VOLUME)Marshal.PtrToStructure(msg.LParam, typeof(NativeMethods.DEV_BROADCAST_VOLUME));
devEvent = DeviceChangeEvent.VolumeRemoval;
devDetails = DrivesFromMask(dbv.dbcv_unitmask);
}
else if (db.dbch_devicetype == NativeMethods.DBT_DEVTYP.PORT)
{
NativeMethods.DEV_BROADCAST_PORT dbp = (NativeMethods.DEV_BROADCAST_PORT)Marshal.PtrToStructure(msg.LParam, typeof(NativeMethods.DEV_BROADCAST_PORT));
devEvent = DeviceChangeEvent.PortRemoval;
devDetails = dbp.dbcp_name;
}
break;
default:
Trace.Assert(false, "Invalid msg.WParam.");
break;
} // end switch (nEventType)
Trace.WriteLine(String.Format("*** DeviceChangeWindow.OnDeviceChange(), {0}, {1}, {2}({3})", devEvent, devDetails, Thread.CurrentThread.Name, Thread.CurrentThread.GetHashCode()));
// let's figure out what to do with the WM_DEVICECHANGE message
// after we get out of this loop so we don't miss any messages.
if (DeviceChangedMsg != null)
{
DeviceChangedMsg.BeginInvoke(devEvent, devDetails, null, null);
}
} // end if (lpdb)
msg.Result = new IntPtr(1); // true
return;
}
