如何显示错误信息，当用户选择超过1天，然后单击复选框半天？

Question

我有两个数据报警器，分别是datepickerFrom和datepickerto。我想显示一个错误信息，当用户选择超过1天，并检查半天复选框，然后单击按钮提交，它将显示和错误消息。

例如:选中1/6/2022-3/6/2022，然后单击复选框半天。当点击提交按钮时，它会显示一条错误消息，比如“对不起，半天内你不能选择超过一个日期！”

这是我检查错误的代码

Private Function ErrorFree() As Boolean 

If datepickerFrom.Date > datepickerto.Date Then 
   If chkHalfDay.Checked = True Then 
       DisplayMessage("error", "ERROR", "Sorry, You can't pick more than 1 date for half day!")
   Return False
   Exit Function
   End If
End If
Return True
End Function

Answer 1

我终于得到答案了！这是密码。然后在datepickerFrom_DateChanged和datepickerto_DateChanged中调用该函数。

    Private Function CalculateDaysBetweenDates() As Integer
        Dim dateFrom As DateTime = Convert.ToDateTime(datepickerFrom.Date)
        Dim dateTo As DateTime = Convert.ToDateTime(datepickerto.Date)
        Dim ts As TimeSpan = dateTo.Subtract(dateFrom)
        If Convert.ToInt32(ts.Days) > 0 Then

            radHalfday.Enabled = False
        Else
            radHalfday.Enabled = True
        End If
        Return 1
    End Function