About Using the form Deactivate Event ?

Hi everyone,

I am trying to use the deactive event of a form. Please see my below example 

private void frmMain_Deactivate(object sender, EventArgs e)
{
    try
    {
         .....
         if (blnSaveData == false)
         {
             Result = MessageBox.Show ("You haven't saved data yet !", "",  MessageBoxButtons.YesNo, MessageBoxIcon.Warning);
             if (Result == DialogResult.Yes)
             { ....}
         }  
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message, null,  MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
    }
}

When running to the statement MessageBox.Show, it call back the event again many times. But, I don't want to this happen, I only want to show the message and execute remain lines then exit the event.

Are there anyone know how can I do that ?

Thanks and regards,

Tai