private void BtnASN_Click(object sender, RoutedEventArgs e)
{
if (asnForm == null || asnForm.IsActive)
{
asnForm = new ASN();
asnForm.Show();
//Add a event handler to set null our window object when it will be closed
asnForm.Closed += new EventHandler(newasnForm_Closed);
}
//If the window was created and your window isn't active
//we call the method Activate to call the specific window to front
else
{
asnForm.Activate();
}
}
void newasnForm_Closed(object sender, EventArgs e)
{
asnForm = null;
}