WPF中TreeView控件的用法

public static void SelectObject(this TreeView treeView, object obj)
public static void SelectObject(this TreeView treeView, object obj, bool selected)
public static bool IsObjectSelected(this TreeView treeView, object obj)
public static bool IsObjectFocused(this TreeView treeView, object obj)
public static void ExpandObject(this TreeView treeView, object obj)
public static void ExpandObject(this TreeView treeView, object obj, bool expanded)
public static bool IsObjectExpanded(this TreeView treeView, object obj)
public static TreeViewItem GetParentItem(this TreeViewItem item)

    public static class TreeViewTools
    {
        /// <summary>
        /// Returns the TreeViewItem of a data bound object.
        /// </summary>
        /// <param name="treeView">TreeView</param>
        /// <param name="obj">Data bound object</param>
        /// <returns>The TreeViewItem of the data bound object or null.</returns>
        public static TreeViewItem GetItemFromObject(this TreeView treeView, object obj)
        {
            try
            {
                DependencyObject dObject = GetContainerFormObject(treeView, obj);
                TreeViewItem tvi = dObject as TreeViewItem;
                while (tvi == null)
                {
                    dObject = VisualTreeHelper.GetParent(dObject);
                    tvi = dObject as TreeViewItem;
                }
                return tvi;
            }
            catch { }
            return null;
        }

        private static DependencyObject GetContainerFormObject(ItemsControl item, object obj)
        {
            if (item == null)
                return null;

            DependencyObject dObject = null;
            dObject = item.ItemContainerGenerator.ContainerFromItem(obj);

            if (dObject != null)
                return dObject;

            var query = from childItem in item.Items.Cast<object>()
                        let childControl = item.ItemContainerGenerator.ContainerFromItem(childItem) as ItemsControl
                        select GetContainerFormObject(childControl, obj);

            return query.FirstOrDefault(i => i != null);
        }

        /// <summary>
        /// Selects a data bound object of a TreeView.
        /// </summary>
        /// <param name="treeView">TreeView</param>
        /// <param name="obj">Data bound object</param>
        public static void SelectObject(this TreeView treeView, object obj)
        {
            treeView.SelectObject(obj, true);
        }

        /// <summary>
        /// Selects or deselects a data bound object of a TreeView.
        /// </summary>
        /// <param name="treeView">TreeView</param>
        /// <param name="obj">Data bound object</param>
        /// <param name="selected">select or deselect</param>
        public static void SelectObject(this TreeView treeView, object obj, bool selected)
        {
            var tvi = treeView.GetItemFromObject(obj);
            if (tvi != null)
            {
                tvi.IsSelected = selected;
            }
        }

        /// <summary>
        /// Returns if a data bound object of a TreeView is selected.
        /// </summary>
        /// <param name="treeView">TreeView</param>
        /// <param name="obj">Data bound object</param>
        /// <returns>Returns true if the object is selected, and false if it is not selected or obj is not in the tree.</returns>
        public static bool IsObjectSelected(this TreeView treeView, object obj)
        {
            var tvi = treeView.GetItemFromObject(obj);
            if (tvi != null)
            {
                return tvi.IsSelected;
            }
            return false;
        }

        /// <summary>
        /// Returns if a data bound object of a TreeView is focused.
        /// </summary>
        /// <param name="treeView">TreeView</param>
        /// <param name="obj">Data bound object</param>
        /// <returns>Returns true if the object is focused, and false if it is not focused or obj is not in the tree.</returns>
        public static bool IsObjectFocused(this TreeView treeView, object obj)
        {
            var tvi = treeView.GetItemFromObject(obj);
            if (tvi != null)
            {
                return tvi.IsFocused;
            }
            return false;
        }

        /// <summary>
        /// Expands a data bound object of a TreeView.
        /// </summary>
        /// <param name="treeView">TreeView</param>
        /// <param name="obj">Data bound object</param>
        public static void ExpandObject(this TreeView treeView, object obj)
        {
            treeView.ExpandObject(obj, true);
        }

        /// <summary>
        /// Expands or collapses a data bound object of a TreeView.
        /// </summary>
        /// <param name="treeView">TreeView</param>
        /// <param name="obj">Data bound object</param>
        /// <param name="expanded">expand or collapse</param>
        public static void ExpandObject(this TreeView treeView, object obj, bool expanded)
        {
            var tvi = treeView.GetItemFromObject(obj);
            if (tvi != null)
            {
                tvi.IsExpanded = expanded;
                if (expanded)
                {
                    // update layout, so that following calls to f.e. SelectObject on child nodes will 
                    // find theire TreeViewNodes
                    treeView.UpdateLayout();
                }
            }
        }

        /// <summary>
        /// Returns if a douta bound object of a TreeView is expanded.
        /// </summary>
        /// <param name="treeView">TreeView</param>
        /// <param name="obj">Data bound object</param>
        /// <returns>Returns true if the object is expanded, and false if it is collapsed or obj is not in the tree.</returns>
        public static bool IsObjectExpanded(this TreeView treeView, object obj)
        {
            var tvi = treeView.GetItemFromObject(obj);
            if (tvi != null)
            {
                return tvi.IsExpanded;
            }
            return false;
        }

        /// <summary>
        /// Retuns the parent TreeViewItem.
        /// </summary>
        /// <param name="item">TreeViewItem</param>
        /// <returns>Parent TreeViewItem</returns>
        public static TreeViewItem GetParentItem(this TreeViewItem item)
        {
            var dObject = VisualTreeHelper.GetParent(item);
            TreeViewItem tvi = dObject as TreeViewItem;
            while (tvi == null)
            {
                dObject = VisualTreeHelper.GetParent(dObject);
                tvi = dObject as TreeViewItem;
            }
            return tvi;
        }
    }