Private Sub mdiMAIN_FormClosing(ByVal sender As System.Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles MyBase.FormClosing

        Dim Message As String = "Sei sicuro di voler uscire?"
        Dim Caption As String = "Conferma"
        Dim Buttons As MessageBoxButtons = MessageBoxButtons.YesNo
        Dim msgIcon As MessageBoxIcon = MessageBoxIcon.Question

        Dim Result As DialogResult

        Result = MessageBox.Show(Message, Caption, Buttons, msgIcon)

        If Result = DialogResult.Yes Then
            e.Cancel = False
        Else
            e.Cancel = True
        End If

    End Sub