主题：日期比较

datacolchanging事件

If e.datacol.name = "出差时艰" then

    If e.NewValue < date.Today Then

        msgbox("有误")

        e.cancel = true

    End If

End If

1、规范你输入的字符，必须是同一种格式；

2、参考代码

Dim str As String = "2017年11月7日-12月8日"
Dim ary1() As String = str.split("-")
Dim ary2() As String = ary1(0).split(new Char() {"年", "月", "日"})
Dim ary3() As String = ary1(1).split(new Char() {"年", "月", "日"})
Dim d1 As Date = new Date(ary2(0), ary2(1), ary2(2))
Dim d2 As Date = new Date(ary2(0), ary3(0), ary3(1))
msgbox(d1)
msgbox(d2)
If d1 > d2 Then
    msgbox("不正确")
ElseIf d1 < Date.today Then
    msgbox("开始日期不能小于今天")
End If

If e.DataCol.name = "时限" Then
    Dim str As String = e.NewValue
    Dim ary1() As String = str.split("-")
    Dim ary2() As String = ary1(0).split(new Char() {"年", "月", "日"})
    Dim ary3() As String = ary1(1).split(new Char() {"年", "月", "日"})
    Dim d1 As Date = new Date(ary2(0), ary2(1), ary2(2))
    Dim d2 As Date = new Date(ary2(0), ary3(0), ary3(1))
    msgbox(d1)
    msgbox(d2)
    If d1 > d2 Then
        msgbox("不正确")
    ElseIf d1 <= Date.today Then
        msgbox("开始日期不能小于今天")
    End If
End If

validating事件

Dim d As String = e.sender.text
If d <> Nothing AndAlso d <= Date.today Then
    msgbox("不能早于今天")
    e.cancel = True
End If

validating事件

Dim d1 As Date = e.Form.Controls("DateTimePicker1").value
Dim d2 As String = e.Form.Controls("DateTimePicker2").text
If d1 <> Nothing AndAlso d2 <> Nothing AndAlso d1 > d2 Then
    msgbox("开始不能大于结束")
    e.cancel = True
End If