wpf mvvm模式下，如何实现右键选中TreeView.SelectItem ?????

Question

TreeView.SelectItem 默认右键选中不了的。 
在普通xaml/cs模式下可以用这种方式来通过右键设置TreeView的SelectItem: private void treeview_MouseRightButtonDown(object sender, MouseButtonEventArgs e)
        {
            var treeViewItem = e.Source as TreeViewItem;
            if (treeViewItem != null)
            {
                treeViewItem.Focus();
                e.Handled = true;
            }
        }
但是这个种方式在mvvm下不适用treeViewItem 获取到是null , e.Source实际上是TreeView本身,因为我是用ItemSource="Binding ObvList"这样的方式设置数据源。  右键获取不了TreeViewItem了  有什么解决办法没， 求指教。

Answer 1

ok 自己解决了。   private void treeview_MouseRightButtonDown(object sender, MouseButtonEventArgs e)
        {
            #region xaml/cs下右键选中方案
            //var treeViewItem = e.Source as TreeViewItem;
            //if (treeViewItem != null)
            //{
            //    treeViewItem.Focus();
            //    e.Handled = true;
            //}
            #endregion            #region mvvm模式下右键选中方案
            SelectItemByRightClickOfMvvm(treeview);
            #endregion
        } public TreeViewItem SelectItemByRightClickOfMvvm(ItemsControl source)
        {
            if (!(source is TreeView) && !(source is TreeViewItem))
            {
                throw new ArgumentException("只支持参数为TreeView或者TreeViewItem", "source");
            }
            foreach (object item in source.Items)
            {
                TreeViewItem currentItem = source.ItemContainerGenerator.ContainerFromItem(item) as TreeViewItem;
                Point mousePosition = Mouse.GetPosition(currentItem);
                Rect itemRect = VisualTreeHelper.GetDescendantBounds(currentItem);
                // 可能是选中的项，也可能是选中项的父节点
                if (itemRect.Contains(mousePosition))
                {
                    // 看看是不是它的孩子被选中了，否则就是它自己被选中了              
                    if (currentItem.IsExpanded)
                    {
                        // 只判断展开的项
                        TreeViewItem selectedItem = SelectItemByRightClickOfMvvm(currentItem);
                        if (selectedItem != null)
                        {
                            selectedItem.IsSelected = true;
                            return selectedItem;
                        }
                    }
                    currentItem.IsSelected = true;                    return currentItem;
                }
            }
            return null;
        }
一个递归， 搞定~