Question

我正在写一个家庭作业计划器，我有一个ListView元素。

我正在寻找一个代码段，当我点击列标题时，我可以按字母顺序排列列。如果它已经按升序排序，则切换到降序，反之亦然，然后按默认/第一个排序，即＆＃34; status＆＃34;在下面的屏幕截图中。

我用谷歌搜索过，找不到任何可以使用的东西，你能帮助我吗？

screenshot

Private Sub ColumnClick(ByVal sender As Object, _
    ByVal e As System.Windows.Forms.ColumnClickEventArgs) _
    Handles lvKalender.ColumnClick

    Select Case e.Column
        ' Nach Namen sortieren
        Case 0
            If lvKalender.Columns.Item(0).ListView.Sorting <> SortOrder.Descending Then
                lvKalender.Columns.Item(0).ListView.Sorting = SortOrder.Descending
            ElseIf lvKalender.Columns.Item(0).ListView.Sorting <> SortOrder.Ascending Then
                lvKalender.Columns.Item(0).ListView.Sorting = SortOrder.Ascending
            End If
        Case 1
            If (1).ListView.Sorting <> SortOrder.Descending Then
                lvKalender.Columns.Item(1).ListView.Sorting = SortOrder.Descending
            ElseIf lvKalender.Columns.Item(1).ListView.Sorting <> SortOrder.Ascending Then
                lvKalender.Columns.Item(1).ListView.Sorting = SortOrder.Ascending
            End If
        Case 2
            If lvKalender.Columns.Item(2).ListView.Sorting <> SortOrder.Descending Then
                lvKalender.Columns.Item(2).ListView.Sorting = SortOrder.Descending
            ElseIf lvKalender.Columns.Item(2).ListView.Sorting <> SortOrder.Ascending Then
                lvKalender.Columns.Item(2).ListView.Sorting = SortOrder.Ascending
            End If
        Case 3
            If lvKalender.Columns.Item(3).ListView.Sorting <> SortOrder.Descending Then
                lvKalender.Columns.Item(3).ListView.Sorting = SortOrder.Descending
            ElseIf lvKalender.Columns.Item(3).ListView.Sorting <> SortOrder.Ascending Then
                lvKalender.Columns.Item(3).ListView.Sorting = SortOrder.Ascending
            End If
        Case 4
            If lvKalender.Columns.Item(4).ListView.Sorting <> SortOrder.Descending Then
                lvKalender.Columns.Item(4).ListView.Sorting = SortOrder.Descending
            ElseIf lvKalender.Columns.Item(4).ListView.Sorting <> SortOrder.Ascending Then
                lvKalender.Columns.Item(4).ListView.Sorting = SortOrder.Ascending
            End If
        Case 5
            If lvKalender.Columns.Item(5).ListView.Sorting <> SortOrder.Descending Then
                lvKalender.Columns.Item(5).ListView.Sorting = SortOrder.Descending
            ElseIf lvKalender.Columns.Item(5).ListView.Sorting <> SortOrder.Ascending Then
                lvKalender.Columns.Item(5).ListView.Sorting = SortOrder.Ascending
            End If
        Case 6
            If lvKalender.Columns.Item(6).ListView.Sorting <> SortOrder.Descending Then
                lvKalender.Columns.Item(6).ListView.Sorting = SortOrder.Descending
            ElseIf lvKalender.Columns.Item(6).ListView.Sorting <> SortOrder.Ascending Then
                lvKalender.Columns.Item(6).ListView.Sorting = SortOrder.Ascending
            End If
    End Select

End Sub

Answer 1

如果我理解你的问题，你想在ListView中对一列日期（可能还有一些值???）进行排序。问题是ListView中的所有内容都是字符串/文本。一些子项目（cols）可能看起来像一样，但这只是因为这是你的大脑翻译/解释它们的方式 - 它们实际上就是字符串。

这样做的影响是排序有数字的文本很少有用。例如，"90"的排序总是高于"300"，因为"9"＆gt; "3"和"19.08.2014"排序高于"10.01.2019"。数字和数字的值不相同。

要按文字以外的其他内容排序，您需要ListViewItemSorter。这个是日期：

Friend Class ListViewItemDateComparer
    Implements IComparer
    Private col As Integer
    Private _sort As SortOrder = SortOrder.Ascending

    Public Sub New(column As Integer, sort As Windows.Forms.SortOrder)
        col = column
        _sort = sort
    End Sub

    Public Function Compare(x As Object,
                 y As Object) As Integer Implements System.Collections.IComparer.Compare
        Dim returnVal As Integer = -1

        ' parse LV contents back to DateTime value
        Dim dtX As DateTime = DateTime.Parse(CType(x, ListViewItem).SubItems(col).Text)
        Dim dtY As DateTime = DateTime.Parse(CType(y, ListViewItem).SubItems(col).Text)

        ' compare
        returnVal = DateTime.Compare(dtX, dtY)

        If _sort = SortOrder.Descending Then
            returnVal *= -1
        End If
        Return returnVal

    End Function
End Class

使用它：

Dim LVSorter = New ListViewItemDateComparer(COL_TO_SORT, Sort_Order)
myLV.ListViewItemSorter = LVSorter

COL_TO_SORT将是您要排序的包含日期的列/子项索引。

Sort_Order将是标准的WinForms SortOrder（SortOrder.Ascending等）

比较其他数据类型，例如Decimal，克隆Comparer并更改进行比较的3行：

' parse LV contents back to Decimal value
Dim dtX As Decimal = Decimal.Parse(CType(x, ListViewItem).SubItems(col).Text)
Dim dtY As Decimal = Decimal.Parse(CType(y, ListViewItem).SubItems(col).Text)

' compare
returnVal = Decimal.Compare(dtX, dtY)

Answer 2

Private Sub ColumnClick(ByVal sender As Object, _
    ByVal e As System.Windows.Forms.ColumnClickEventArgs) _
    Handles lvKalender.ColumnClick

 If lvKalender.Columns.Item(e.Column).ListView.Sorting <> SortOrder.Descending Then
     lvKalender.Columns.Item(e.Column).ListView.Sorting = SortOrder.Descending
  ElseIf lvKalender.Columns.Item(e.Column).ListView.Sorting <> SortOrder.Ascending Then
     lvKalender.Columns.Item(e.Column).ListView.Sorting = SortOrder.Ascending
 End If

End Sub

Answer 3

Private Sub ListViewProcess_ColumnClick(sender As Object, e As ColumnClickEventArgs) Handles ListViewProcess.ColumnClick
    sender.AutoResizeColumn(e.Column, ColumnHeaderAutoResizeStyle.HeaderSize)
    If sender.Columns.Item(e.Column).ListView.Sorting <> SortOrder.Descending Then
        sender.Columns.Item(e.Column).ListView.Sorting = SortOrder.Descending
    ElseIf sender.Columns.Item(e.Column).ListView.Sorting <> SortOrder.Ascending Then
        sender.Columns.Item(e.Column).ListView.Sorting = SortOrder.Ascending
    End If
End Sub

单击标题时如何对Listview列进行排序

3 个答案: