vb.net - 代码运行了两次

Question

我已经得到了开始日期来验证是否在结束日期之后并显示消息，但是当我输入以下代码时，它似乎运行了两次代码我已经尝试了所有的句柄离开尝试它没有工作我也把它进入一个新线程，没有工作，也进入一个函数，我在这个问题上没有工作

这是代码

Function DateCompare(ByVal Start As Date, ByVal Finish As Date, ByVal WhichDate As String)
  If WhichDate = "DateIn" Then
    If DateTime.Compare(Start, Finish) > 0 Then
      MsgBox("Dates Are Invalid : Date In Cannot be after Date Out, Please Amend", vbExclamation, "Dates Are Incorrect")
      Return False
      Exit Function
    Else
      Return True
    End If
  Else
    If DateTime.Compare(Finish, Start) < 0 Then
      MsgBox("Dates Are Invalid : Date Out Cannot be before Date In, Please Amend", vbExclamation, "Dates Are Incorrect")
      Return False
      Exit Function
    Else
      Return True
    End If
  End If
End Function

Private Sub dtpDateTimeIn_leave(ByVal sender As Object, ByVal e As EventArgs) Handles dtpDateTimeIn.Leave
  Dim result As Boolean
  result = DateCompare(dtpDateTimeIn.Value, dtpDateTimeOut.Value, "DateIn")
  If result = False Then
    dtpDateTimeIn.Focus()
  End If
End Sub

Private Sub dtpDateTimeOut_leave(ByVal sender As Object, ByVal e As EventArgs) Handles dtpDateTimeOut.Leave
  Dim result As Boolean
  result = DateCompare(dtpDateTimeIn.Value, dtpDateTimeOut.Value, "DateOut")
  If result = False Then
    dtpDateTimeOut.Focus()
  End If
End Sub

Answer 1

尝试改用Validating事件。他们是为此而生的：

Private Sub dtpDateTimeIn_Validating(ByVal sender As Object, ByVal e As CancelEventArgs) Handles dtpDateTimeIn.Validating
  e.Cancel = Not DateCompare(dtpDateTimeIn.Value, dtpDateTimeOut.Value, "DateIne")
End Sub

Private Sub dtpDateTimeOut_Validating(ByVal sender As Object, ByVal e As CancelEventArgs) Handles dtpDateTimeOut.Validating
  e.Cancel = Not DateCompare(dtpDateTimeIn.Value, dtpDateTimeOut.Value, "DateOut")
End Sub