WM_DROPFILES

void CWnd::OnDropFiles(HDROP hDropInfo)
{
CWaitCursor wait;

int count = ::DragQueryFileW( hDropInfo, 0xffffffff, 0, 0 );

for( int i = 0; i < count; i++ )
{
WCHAR path[1024];
::DragQueryFileW( hDropInfo, i, path, 1024 );

load( path );
break;
}

::DragFinish( hDropInfo );

CWnd::SetForegroundWindow();

// CWnd::OnDropFiles(hDropInfo);
}