[Dev Saeed]

الموضوع بسيط جداً  ضع الامر e.Cancel = True  في حدث Form_FormClosing هكذا :

كود :

 Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
       e.Cancel = True
   End Sub