接下来是缩进，没有缩进的Tree怎么看都不顺眼。
首先，定义节点深度Depth(注：回叫方法暂没有代码，以后要用到)：
1: /// <summary>
2: /// Using a DependencyProperty as the backing store for Depth. This enables animation, styling, binding, etc...
3: /// </summary>
4: public static readonly DependencyProperty DepthProperty =
5: DependencyProperty.Register("Depth", typeof(int), typeof(FancyTreeViewItem),
6: new PropertyMetadata(0, new PropertyChangedCallback(FancyTreeViewItem.OnDepthPropertyChanged))
7: );
8:
1: /// <summary>
2: /// Gets or sets the node depth level in tree
3: /// </summary>
4: public int Depth
5: {
6: get { return (int)GetValue(DepthProperty); }
7: set { SetValue(DepthProperty, value); }
8: }
9:
1: /// <summary>
2: /// Call back when Depth property has been changed
3: /// </summary>
4: /// <param name="o">The target object</param>
5: /// <param name="e">>The property changed event arrguments</param>
6: private static void OnDepthPropertyChanged(DependencyObject o, DependencyPropertyChangedEventArgs e)
7: {
8:
9: }
10:
接下来就是写出计算节点在树中深度值的方法：
1: /// <summary>
2: /// For getting the item depth level
3: /// </summary>
4: /// <returns>The result depth level</returns>
5: private int GetDepthLevel()
6: {
7: int depthLevel = 0;
8: FrameworkElement element = this;
9:
10: while (element.Parent != null)
11: {
12: var parent = element.Parent as FancyTreeViewItem;
13:
14: if (parent != null)
15: {
16: depthLevel++;
17: ////depthLevel = parent.GetDepthLevel() + 1;
18: }
19:
20: element = element.Parent as FrameworkElement;
21: }
22:
23: return depthLevel;
24: }
25:
绑定样式的时候把缩进量放进去，在public override void OnApplyTemplate()中添加：
1: if (this.Indent != null)
2: {
3: this.Indent.Width = this.GetDepthLevel() * 20;
4: }
5:
最后把Boder的边框颜色去掉，运行看效果：
图4.1 带缩进的效果图