Question

我在WPF应用程序（Framework 3.5 SP1）中遇到了TreeView问题。这是一个拥有2个数据级别的TreeVIew。我以特定方式展开/折叠第一级的项目（只需在TreeViewItem上单击鼠标）。再次当我展开第一级TreeViewItem时，我将一些二级TreeViewItem添加到组中（这是一个重要的细节，事实上，如果我不添加项目，则问题不会发生）。一切正常，直到TreeView失去焦点。例如，如果我在第一个位置展开TreeViewItem，同时将一个元素添加到第二个级别，那么我单击一个按钮（让TreeView失去焦点），然后再次单击TreeViewItem在第三个位置展开它，由鼠标位置命中测试得到的TreeViewItem不是“真正的”TreeViewItem（在本例中是第三个），而是一个位于比单击的位置更高的TreeViewItem （在这种情况下是第二个）。我试图在TreeView-LostFocus事件上使用UpdateLayout方法，但没有结果。可能我需要一个相反的方法：从UI开始，刷新包含TreeViewItems位置的对象。你能帮我么？谢谢！ Pileggi

这是代码：

   ' in this way I tried to put remedy at the problem, but it doesn't work.
    Private Sub tvArt_LostFocus(ByVal sender As Object, ByVal e As RoutedEventArgs) Handles tvArt.LostFocus
        Me.tvArt.UpdateLayout()

        e.Handled = True
    End Sub

    ' here I expand / collapse the items of the first level of my TreeView
    Private Sub tvArt_PreviewMouseUp(ByVal sender As System.Object, ByVal e As MouseButtonEventArgs) Handles tvArt.PreviewMouseUp
        Dim p As Point = Nothing
        Dim tvi As TreeViewItem = getItemFromMousePosition(Of TreeViewItem)(p, e.OriginalSource, Me.tvArt)
        If tvi Is Nothing = False Then
            If tvi.HasItems Then
                Dim be As BindingExpression = BindingOperations.GetBindingExpression(tvi, TreeViewItem.ItemsSourceProperty)
                Dim ri As P_RicambiItem = DirectCast(be.DataItem, P_RicambiItem)
                If ri.isExpanded = False then
                    ' here I add items to the second level collection
                End If

                ri.isExpanded = Not ri.isExpanded
            End If
        End If

        e.Handled = True
    End Sub

    Private Function getItemFromMousePosition(Of childItem As DependencyObject)(ByRef p As Point, ByVal sender As UIElement, _
        ByVal _item As UIElement) As childItem

        p = sender.TranslatePoint(New Point(0, 0), _item)
        Dim obj As DependencyObject = DirectCast(_item.InputHitTest(p), DependencyObject)
        While obj Is Nothing = False AndAlso TypeOf obj Is childItem = False
            obj = VisualTreeHelper.GetParent(obj)
        End While
        Return DirectCast(obj, childItem)
    End Function

Answer 1

我找到了这个解决方案（但我不太喜欢它）。问题取决于添加的项目，因为某些原因，wpf不记得存在。然后我用一个清除并重新添加源集合中所有项目的方法进行“手动”刷新：

Public Sub RefreshData(ByVal RicambiListPass As ObservableCollection(Of P_RicambiItem))
    Dim l As New List(Of P_RicambiItem)
    l.AddRange(RicambiListPass)
    _RicambiList.Clear()
    For Each i As P_RicambiItem In l
        _RicambiList.Add(i)
    Next
End Sub

WPF在失去焦点时刷新TreeView

1 个答案: