public void WndProc(ref Message m)
{
int devType;
char c;
try
{
if (m.Msg == WM_DEVICECHANGE)
{
// WM_DEVICECHANGE can have several meanings depending on the WParam value...
switch (m.WParam.ToInt32())
{
case DBT_DEVNODES_CHANGED:
RemovableDriveDetectorEventHandler tempDeviceChanged = DeviceChanged;
if (tempDeviceChanged != null)
{
RemovableDriveDetectorEventArgs e = new RemovableDriveDetectorEventArgs();
tempDeviceChanged(this, e);
}
break;
//
// New device has just arrived
//
case DBT_DEVICEARRIVAL:
devType = Marshal.ReadInt32(m.LParam, 4);
if (devType == DBT_DEVTYP_VOLUME)
{
DEV_BROADCAST_VOLUME vol;
vol = (DEV_BROADCAST_VOLUME)
Marshal.PtrToStructure(m.LParam, typeof(DEV_BROADCAST_VOLUME));
// Get the drive letter
c = DriveMaskToLetter(vol.dbcv_unitmask);
//
// Call the client event handler
//
// We should create copy of the event before testing it and
// calling the delegate - if any
RemovableDriveDetectorEventHandler tempDeviceArrived = DeviceArrived;
if (tempDeviceArrived != null)
{
RemovableDriveDetectorEventArgs e = new RemovableDriveDetectorEventArgs();
e.Drive = c + ":\\";
tempDeviceArrived(this, e);
// Register for query remove if requested
if (e.HookQueryRemove)
{
// If something is already hooked, unhook it now
if (mDeviceNotifyHandle != IntPtr.Zero)
{
RegisterForDeviceChange(false, null);
}
RegisterQuery(c + ":\\");
}
} // if has event handler
}
break;
//
// Device is about to be removed
// Any application can cancel the removal
//
case DBT_DEVICEQUERYREMOVE:
devType = Marshal.ReadInt32(m.LParam, 4);
if (devType == DBT_DEVTYP_HANDLE)
{
// TODO: we could get the handle for which this message is sent
// from vol.dbch_handle and compare it against a list of handles for
// which we have registered the query remove message (?)
//DEV_BROADCAST_HANDLE vol;
//vol = (DEV_BROADCAST_HANDLE)
// Marshal.PtrToStructure(m.LParam, typeof(DEV_BROADCAST_HANDLE));
// if ( vol.dbch_handle ....
//
// Call the event handler in client
//
RemovableDriveDetectorEventHandler tempQuery = DeviceQueryRemove;
if (tempQuery != null)
{
RemovableDriveDetectorEventArgs e = new RemovableDriveDetectorEventArgs();
e.Drive = mCurrentDrive; // drive which is hooked
tempQuery(this, e);
// If the client wants to cancel, let Windows know
if (e.Cancel)
{
m.Result = (IntPtr)BROADCAST_QUERY_DENY;
}
else
{
// Change 28.10.2007: Unregister the notification, this will
// close the handle to file or root directory also.
// We have to close it anyway to allow the removal so
// even if some other app cancels the removal we would not know about it...
RegisterForDeviceChange(false, null); // will also close the mFileOnFlash
}
}
}
break;
//
// Device has been removed
//
case DBT_DEVICEREMOVECOMPLETE:
devType = Marshal.ReadInt32(m.LParam, 4);
if (devType == DBT_DEVTYP_VOLUME)
{
devType = Marshal.ReadInt32(m.LParam, 4);
if (devType == DBT_DEVTYP_VOLUME)
{
DEV_BROADCAST_VOLUME vol;
vol = (DEV_BROADCAST_VOLUME)
Marshal.PtrToStructure(m.LParam, typeof(DEV_BROADCAST_VOLUME));
c = DriveMaskToLetter(vol.dbcv_unitmask);
//
// Call the client event handler
//
RemovableDriveDetectorEventHandler tempDeviceRemoved = DeviceRemoved;
if (tempDeviceRemoved != null)
{
RemovableDriveDetectorEventArgs e = new RemovableDriveDetectorEventArgs();
e.Drive = c + ":\\";
tempDeviceRemoved(this, e);
}
// TODO: we could unregister the notify handle here if we knew it is the
// right drive which has been just removed
//RegisterForDeviceChange(false, null);
}
}
break;
}
}
}
catch (Exception)
{
}
}
/// <summary>
/// This function receives all the windows messages for this window (form).
/// We call the DriveDetector from here so that is can pick up the messages about
/// drives arrived and removed.
/// </summary>
protected override void WndProc(ref Message m)
{
base.WndProc(ref m);
if (mDetector != null)
{
mDetector.WndProc(ref m);
}
}
