excel - 双消息显示-VBA

Question

在以下代码中，输入错误的值时会显示错误消息。由于字段为空，删除错误值时再次显示错误消息。如何再次停止显示消息？

Private Sub textbox1_Change()
   If TextBox1 < 1 Or TextBox1 > 31 Then
   Beep
   MsgBox "Please enter numbers between 1 and 31."
   TextBox1= ""
   TextBox1.SetFocus
   End If
End Sub

Answer 1

Private Sub textbox1_Change()
    Select Case True
        Case Len(TextBox1.Text) = 0

        Case TextBox1.Value < 1 Or TextBox1.Value > 31
            Beep
            MsgBox "Please enter numbers between 1 and 31."
            TextBox1 = ""
            TextBox1.SetFocus

    End Select
End Sub

或者

Private Sub textbox1_Change()
    If Len(TextBox1.Text) = 0 Then Exit Sub

    If TextBox1 < 1 Or TextBox1 > 31 Then
        Beep
        MsgBox "Please enter numbers between 1 and 31."
        TextBox1 = ""
        TextBox1.SetFocus
    End If
End Sub