Question

我尝试使用计时器事件同步以下3个列表框。

左： ID

中间： Listbox1

右： Listbox2

Private GI_Sync_X_centerLine As Integer

GI_Sync_X_centerLine = (ListBox1.Left + ListBox1.Width + ListBox1.Left) \ 2 (here should be the issue)

Private Sub sync_Tick(sender As Object, e As EventArgs) Handles sync.Tick
        If (ListBox1.TopIndex <> ListBox2.TopIndex) Then            ' out-of-sync
            If (ListBox1.Items.Count = ListBox2.Items.Count) Then   ' both are scrollable
                If ((MousePosition.X - Me.Location.X) < GI_Sync_X_centerLine) Then ' mouse is on the left one
                    ListBox2.TopIndex = ListBox1.TopIndex       ' move the right one to match
                Else
                    ListBox1.TopIndex = ListBox2.TopIndex       ' & v.v.
                End If
            End If
        End If

        If (id.TopIndex <> ListBox2.TopIndex) Then            ' out-of-sync
            If (id.Items.Count = ListBox2.Items.Count) Then   ' both are scrollable
                If ((MousePosition.X - Me.Location.X) < GI_Sync_X_centerLine) Then ' mouse is on the left one
                    ListBox2.TopIndex = id.TopIndex       ' move the right one to match
                Else
                    id.TopIndex = ListBox2.TopIndex       ' & v.v.
                End If
            End If
        End If

        If (id.TopIndex <> ListBox1.TopIndex) Then            ' out-of-sync
            If (id.Items.Count = ListBox1.Items.Count) Then   ' both are scrollable
                If ((MousePosition.X - Me.Location.X) < GI_Sync_X_centerLine) Then ' mouse is on the left one
                    ListBox1.TopIndex = id.TopIndex       ' move the right one to match
                Else
                    id.TopIndex = ListBox1.TopIndex       ' & v.v.
                End If
            End If
        End If
    End Sub

在https://social.msdn.microsoft.com/Forums/vstudio/en-US/38413d0a-7388-4191-a7a6-fd66e469d502/two-listbox-scrollbar-in-synchronisation?forum=wpf找到解决方案，并将其修改为3个列表框。

问题如下：

如果我滚动左侧列表框，其他所有其他人也会滚动。如果我滚动右侧列表框，其他所有其他滚动，但是，如果我尝试滚动中间列表框，其他人不会滚动，而中间会卡在其他人所在的位置。

Answer 1

Public Function GetDescendantByType(element As Visual, type As Type) As Visual
    If element Is Nothing Then
        Return Nothing
    End If
    If element.[GetType]() = type Then
        Return element
    End If
    Dim foundElement As Visual = Nothing
    If TypeOf element Is FrameworkElement Then
        TryCast(element, FrameworkElement).ApplyTemplate()
    End If
    For i As Integer = 0 To VisualTreeHelper.GetChildrenCount(element) - 1
        Dim visual As Visual = TryCast(VisualTreeHelper.GetChild(element, i), Visual)
        foundElement = GetDescendantByType(visual, type)
        If foundElement IsNot Nothing Then
            Exit For
        End If
    Next
    Return foundElement
End Function
Private Sub lb_ScrollChanged(sender As Object, e As ScrollChangedEventArgs)
    Dim _listboxScrollViewer1 As ScrollViewer = TryCast(GetDescendantByType(id, GetType(ScrollViewer)), ScrollViewer)
    Dim _listboxScrollViewer2 As ScrollViewer = TryCast(GetDescendantByType(listBox1, GetType(ScrollViewer)), ScrollViewer)
    Dim _listboxScrollViewer3 As ScrollViewer = TryCast(GetDescendantByType(listBox2, GetType(ScrollViewer)), ScrollViewer)
    _listboxScrollViewer2.ScrollToVerticalOffset(_listboxScrollViewer1.VerticalOffset)
    _listboxScrollViewer3.ScrollToVerticalOffset(_listboxScrollViewer2.VerticalOffset)
    _listboxScrollViewer1.ScrollToVerticalOffset(_listboxScrollViewer3.VerticalOffset)
End Sub

并将lb_ScrollChanged与事件ScrollViewer.ScrollChanged="lb_ScrollChanged"关联到每个ListBox

如果您对该代码有疑问，请回复。

如何在vb.net中同步3个列表框的滚动位置？

1 个答案: