离开文本框时出现VBA Excel错误

Question

我想过一个半透明的文字来显示日期应该如何输入的格式。添加代码后，我发现如果单击我的txtA_DateCR文本框，然后单击另一个文本框或命令按钮，错误将继续提示。

'This was the code that works fine before adding the following 2 below.
Private Sub txtA_DateCR_BeforeUpdate(ByVal Cancel As MSForms.ReturnBoolean)
    If Mid(txtA_DateCR.Value, 4, 2) > 12 Then
        MsgBox "Invalid date, make sure format is (dd/mm/yyyy)", vbCritical
        txtA_DateCR.Value = vbNullString
        txtA_DateCR.SetFocus
        Exit Sub
    End If

    dDate = DateSerial(Year(Date), Month(Date), Day(Date))
    txtA_DateCR.Value = Format(txtA_DateCR.Value, "dd/mm/yyyy")
    dDate = txtA_DateCR.Value
End Sub

'Supposed to change the textbox values to light grey and have the value of dd/mm/yyyy
Private Sub txtA_DateCR_AfterUpdate()

    With txtA_DateCR
    If .Text = "" Then
    .ForeColor = &HC0C0C0
    .Text = "dd/mm/yyyy"
    End If
    End With

End Sub

'When user clicks here, the value of dd/mm/yyyy will disappear and font colour will return back to black
Private Sub txtA_DateCR_Enter()

    With txtA_DateCR
    If .Text = "dd/mm/yyyy" Then
    .ForeColor = &H80000008
    .Text = ""
    End If
    End With

End Sub

Private Sub UserForm_Initialize()

txtA_DateCR.ForeColor = &HC0C0C0
txtA_DateCR.Text = "dd/mm/yyyy"
cmdEnter.SetFocus

End Sub

总结一下，如果用户输入错误的日期格式而不是在我点击文本框时弹出，我只希望弹出错误信息。