private void _form_FormClosing(object sender, FormClosingEventArgs e)
{
if (_launchAppScanner != null)
{
_launchAppScanner.FormClosing -= _form_FormClosing;
_launchAppScanner.EvtQuit -= _launchAppScanner_EvtQuit;
_launchAppScanner.EvtLaunchApp -= _launchAppScanner_EvtLaunchApp;
_launchAppScanner.EvtShowScanner -= launchAppScanner_EvtShowScanner;
}
_launchAppScanner = null;
}