为什么 e.Source 依赖于 TreeView 填充方法? [英] Why e.Source depends on TreeView populating method?

问题描述

我有两棵树:

1. fooTree - 由元素组成，
2. barTree - 由
构建

两棵树都有 MouseRightButtonDown 事件，但 e.Source 类型不同:

1. fooTree - System.Windows.Controls.TreeViewItem
2. barTree - System.Windows.Controls.TreeView

为什么 e.Source 不同?另外，如何获取 barTree 的点击项?

标记:

 <TreeView Name="fooTree" MouseRightButtonDown="fooTree_MouseDown"><TreeViewItem Header="foo"></TreeViewItem><TreeViewItem Header="foo"></TreeViewItem></树视图><TreeView 名称="barTree" MouseRightButtonDown="barTree_MouseDown" ItemsSource="{Binding BarItems}"><TreeView.ItemTemplate><分层数据模板><TextBlock 文本="{绑定}"/></分层数据模板></TreeView.ItemTemplate></树视图>

代码:

public 部分类 Window1 : Window{公共窗口1(){初始化组件()；this.DataContext = this;}公共字符串[] BarItems{获取 { 返回新字符串 [] { "bar", "bar" };}}私人无效barTree_MouseDown(对象发送者，MouseButtonEventArgs e){}私人无效fooTree_MouseDown(对象发送者，MouseButtonEventArgs e){}}

解决方案

不知道为什么会这样，但至少我找到了解决方案:

http:///social.msdn.microsoft.com/Forums/en-US/wpf/thread/f0d3af69-6ecc-4ddb-9526-588b72d5196b/

<块引用>

1. 如果您的处理程序位于 TreeView 上，请使用事件参数并走上视觉父链，直到你找到一个树视图项.然后，选择它.你可以通过使用走可视父链System.Windows.Media.VisualTreeHelper.GetParent.

2. 您可以尝试为 TreeViewItem 类型注册一个类处理程序和鼠标按下事件.然后，您的处理程序只应在鼠标时调用事件通过 TreeViewItem元素.

3. 您可以为 TreeViewItem 类型和上下文注册一个类处理程序菜单打开事件.

所以我的代码是:

private void OnMouseRightButtonDown(object sender, MouseButtonEventArgs e){TreeViewItem treeViewItem = VisualUpwardSearch<TreeViewItem>(e.OriginalSource as DependencyObject) as TreeViewItem;}static DependencyObject VisualUpwardSearch(DependencyObject 源){while (source != null && source.GetType() != typeof(T))source = VisualTreeHelper.GetParent(source);返回源；}

I have two trees:

1. fooTree - made up of elements,
2. barTree - constructed by

Both trees have MouseRightButtonDown event, but the e.Source type differs:

1. fooTree - System.Windows.Controls.TreeViewItem
2. barTree - System.Windows.Controls.TreeView

Why e.Source differs? Also, how can I get the clicked item for the barTree?

Markup:

    <TreeView Name="fooTree" MouseRightButtonDown="fooTree_MouseDown">
        <TreeViewItem Header="foo"></TreeViewItem>
        <TreeViewItem Header="foo"></TreeViewItem>
    </TreeView>

    <TreeView Name="barTree" MouseRightButtonDown="barTree_MouseDown" ItemsSource="{Binding BarItems}">
        <TreeView.ItemTemplate>
            <HierarchicalDataTemplate>
                <TextBlock Text="{Binding}" />
            </HierarchicalDataTemplate>
        </TreeView.ItemTemplate>
    </TreeView>

Code:

public partial class Window1 : Window
{
    public Window1()
    {
        InitializeComponent();
        this.DataContext = this;
    }

    public string[] BarItems
    {
        get { return new string[] { "bar", "bar" }; }
    }

    private void barTree_MouseDown(object sender, MouseButtonEventArgs e) 
    {
    }

    private void fooTree_MouseDown(object sender, MouseButtonEventArgs e) 
    {
    }
}

解决方案

Don't know why this happens, but at least I have found a solution:

http://social.msdn.microsoft.com/Forums/en-US/wpf/thread/f0d3af69-6ecc-4ddb-9526-588b72d5196b/

1. If your handler is on the TreeView, use the OriginalSource property in the event arguments and walk up the visual parent chain until you find a TreeViewItem. Then, select it. You can walk the visual parent chain by using System.Windows.Media.VisualTreeHelper.GetParent.

2. You could try registering a class handler for type TreeViewItem and the mouse down event. Then, your handler should only be called when mouse events pass through TreeViewItem elements.

3. You could register a class handler for type TreeViewItem and the context menu opening event.

So my code is:

private void OnMouseRightButtonDown(object sender, MouseButtonEventArgs e)
{
    TreeViewItem treeViewItem = VisualUpwardSearch<TreeViewItem>(e.OriginalSource as DependencyObject) as TreeViewItem;
}

static DependencyObject VisualUpwardSearch<T>(DependencyObject source)
{
    while (source != null && source.GetType() != typeof(T))
        source = VisualTreeHelper.GetParent(source);

    return source;
}

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