Private Sub TextBox_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox.KeyPress
        'Solo caratteri numerici e separatore decimali

        'Memorizza carattere inputato
        Dim keyInput As String = e.KeyChar.ToString()

        Dim numberFormatInfo As System.Globalization.NumberFormatInfo = System.Globalization.CultureInfo.CurrentCulture.NumberFormat
        'Recupera separatore decimale
        Dim decimalSeparator As String = numberFormatInfo.NumberDecimalSeparator
        ''Recupera separatore migliaia
        'Dim groupSeparator As String = numberFormatInfo.NumberGroupSeparator
        'Recupera separatore segno per negtivi
        Dim negativeSign As String = numberFormatInfo.NegativeSign

        e.Handled = True 'Rifiuta carattere (di default)
        If Char.IsDigit(e.KeyChar) Then e.Handled = False 'Se numero accetta
        If keyInput.Equals(decimalSeparator) And Not (tbQuantita.Text.Contains(decimalSeparator)) Then e.Handled = False 'Se separatore deciamale accetta
        If e.KeyChar = ControlChars.Back Then e.Handled = False 'Se BackSpace accetta
    End Sub