Question

是的，这一定是我曾经遇到的最奇怪的要求。我有三个DateTimePickers，用户可以使用箭头更改日，月和年（每一个）。左/右用于选择日/月/年，向上/向下用于增加或减少。就像默认一样。

现在客户希望这是向上/向下反转，也就是说，如果我有第23天并按下，则应为22.如果月份是3月，我按下，则应该是2月。客户总是对的，是吧？

是否有一些默认设置或我可以为此做些什么，或者我是否必须编写自己的＆＃34;逻辑＆＃34;对此？

编辑：一个子问题;如何查看当前选定的值是日，月还是年？我有这个：

Private Sub InvertedDateTimePicker(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles _
    DTP1.KeyDown, DTP2.KeyDown, DTP3.KeyDown

    Dim dtp As DateTimePicker = sender

    If e.KeyCode = 38 Then 'UP
        '...if the current selection is day.
        'and actually i have to have -2 since the arrow up gave it +1....
        dtp.Value = dtp.Value.AddDays(-1) 
        '...if the current selection is month.
        'and actually i have to have -2 since the arrow up gave it +1....
        dtp.Value = dtp.Value.AddMonth(-1) 
    ElseIf e.KeyCode = 40 Then 'DOWN

    End If
End Sub

Answer 1

没有内置的方法来做这个AFAIK。

但是这个怎么样。它确定哪个值已经改变并反转它：

Private _lastDate As Date
Private _keyDown As Boolean

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    _lastDate = DateTimePicker1.Value
End Sub

Private Sub DateTimePicker1_KeyDown(sender As Object, e As KeyEventArgs) Handles DateTimePicker1.KeyDown
    _keyDown = True
End Sub

Private Sub DateTimePicker1_KeyUp(sender As Object, e As KeyEventArgs) Handles DateTimePicker1.KeyUp
    _keyDown = False
End Sub

Private Sub DateTimePicker1_ValueChanged(sender As Object, e As EventArgs) Handles DateTimePicker1.ValueChanged
    If DateTimePicker1.Value = _lastDate Then Exit Sub
    If Not _keyDown Then Exit Sub
    If _lastDate.Day <> DateTimePicker1.Value.Day Then
        'day has changed
        Dim days As Integer = DateTimePicker1.Value.Day - _lastDate.Day
        _lastDate = _lastDate.AddDays(-1 * days)
    End If
    If _lastDate.Month <> DateTimePicker1.Value.Month Then
        'month has changed 
        Dim months As Integer = DateTimePicker1.Value.Month - _lastDate.Month
        _lastDate = _lastDate.AddMonths(-1 * months)
    End If
    If _lastDate.Year <> DateTimePicker1.Value.Year Then
        'year has changed 
        Dim years As Integer = DateTimePicker1.Value.Year - _lastDate.Year
        _lastDate = _lastDate.AddYears(-1 * years)
    End If
    DateTimePicker1.Value = _lastDate
End Sub

如果更新代码中的值，则必须在更新之前设置_lastDate，否则它也会被反转！

在DateTimePicker中反转箭头的值

1 个答案: