PreviewMouseLeftButtonDown预防SelectionChanged事件

Question

我把ListBoxItems放在画布上了。我可以使用ScrollViewer在画布上拖动和滚动视图，并使用一些鼠标事件。这些鼠标事件似乎覆盖了嵌套在SelectionChanged中的ListBox的ListBox事件，或者选择永远不会进行，因为鼠标事件在ListBox之前捕获了单击。如果有人对这个问题有任何解决办法，我们将不胜感激。谢谢你的时间，这是我的密码。

XAML：

        <ScrollViewer x:Name="objScrollViewer"
                      Grid.Row="0"
                      Grid.Column="1"
                      VerticalScrollBarVisibility="Hidden"
                      HorizontalScrollBarVisibility="Hidden"
                      HorizontalAlignment="Stretch"
                      VerticalAlignment="Stretch"
                      MouseLeftButtonUp ="OnMouseLeftButtonUp"
                      PreviewMouseLeftButtonUp ="OnMouseLeftButtonUp"
                      PreviewMouseLeftButtonDown="OnPreviewMouseLeftButtonDown"
                      PreviewMouseMove="OnPreviewMouseMove"
                      PreviewMouseUp="OnPreviewMouseUp"
                      ScrollChanged="OnScrollViewerScrollChanged">

            <ListBox x:Name="objCoreViewer"
                     ItemsSource="{Binding ItemsSource}"
                     Background="Transparent"
                     SelectionChanged="objCoreViewer_SelectionChanged"
                     ItemTemplateSelector="{DynamicResource CoreViewerDataTemplateSelector}"
                     ItemContainerStyleSelector="{DynamicResource ItemContainerStyleSelector}"
                     PreviewMouseWheel="objCoreViewer_PreviewMouseWheel">

                <!-- Core Map Canvas -->

                <ListBox.ItemsPanel>

                    <ItemsPanelTemplate>
                        <local:CoreViewerCanvas x:Name="objCoreViewerCanvas"
                                Background="Transparent"
                                ClipToBounds="True">
                            <local:CoreViewerCanvas.LayoutTransform>
                                <ScaleTransform ScaleX="{Binding Path=Value, ElementName=ZoomSlider}"
                                                ScaleY="{Binding Path=Value, ElementName=ZoomSlider}" />
                            </local:CoreViewerCanvas.LayoutTransform>
                        </local:CoreViewerCanvas>
                    </ItemsPanelTemplate>

                </ListBox.ItemsPanel>

            </ListBox>

        </ScrollViewer>

C#：

这从来没有被称为

    private void objCoreViewer_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
    }

，这确实被称为

    private void OnPreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
    {
        var mousePos = e.GetPosition(objScrollViewer);
        if (mousePos.X <= objScrollViewer.ViewportWidth && mousePos.Y < 
            objScrollViewer.ViewportHeight)
        {
            objScrollViewer.Cursor = Cursors.SizeAll;
            lastDragPoint = mousePos;
            Mouse.Capture(objScrollViewer);
        }
    }

编辑1:

我将ScrollViewer事件属性从PreviewMouseLeftButtonDown更改为MouseLeftButtonDown，它现在触发SelectionChanged事件方法，但ScrollViewer现在没有滚动，因为MouseLeftButtonDown事件方法从未被捕获。叹气！

Answer 1

将鼠标事件方法更改为：

    private void OnPreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
    {
        var mousePos = e.GetPosition(objScrollViewer);
        if (mousePos.X <= objScrollViewer.ViewportWidth && mousePos.Y <
            objScrollViewer.ViewportHeight)
        {
            objScrollViewer.Cursor = Cursors.SizeAll;
            lastDragPoint = mousePos;
            Mouse.Capture(objScrollViewer);
        }

        FrameworkElement ctrl = (e.OriginalSource as FrameworkElement);
        if (ctrl != null)
        {
            switch (ctrl.DataContext.GetType().ToString())
            {
                case "GE.GNF.ACUMEN.Library.SIMULATOR_BUNDLE_NODAL_DATA":
                    objCoreViewer.SelectedItem = ctrl.DataContext as SIMULATOR_BUNDLE_NODAL_DATA;
                    break;
                case "GE.GNF.ACUMEN.Library.SIMULATOR_CONTROL_BLADE_NODAL_DATA":
                    objCoreViewer.SelectedItem = ctrl.DataContext as SIMULATOR_CONTROL_BLADE_NODAL_DATA;
                    break;
                default:
                    break;
            }
        }
    }