Composite UI Application Block 之自定义UIElement（二）

目标：让我们建立一个树形结构菜单，具体的说用一个TreeView来显示菜单。先看效果图

 

1、首先我们需要建立一个自定义的TreeView，实现单击事件。

 

namespace CustomUIElements
...{
    public delegate void NodeClickedEvent(object sender, TreeNode nodeClicked);

    public class ClickableTreeNode : TreeNode
    ...{
        ClickableTreeView _parent = null;
        public event EventHandler NodeClick;

        private bool _needsSetup = false;
        public bool NeedsSetup
        ...{
            get ...{ return _needsSetup; }
        }
        public ClickableTreeNode()
            : base()
        ...{
            _needsSetup = true;
        }

        public new ClickableTreeView TreeView
        ...{
            get ...{ return _parent; }
        }

        public void SetUp(ClickableTreeView tv)
        ...{
            ClickableTreeView clickable = tv as ClickableTreeView;
            if (clickable == null) throw new Exception("The clickable tree node was added to a non-clickable tree view");

            _parent = clickable;
            // register for the node clicked event, when *a* node gets clicked
            clickable.NodeClicked += new NodeClickedEvent(clickable_NodeClicked);

            _needsSetup = false;
        }

        public ClickableTreeNode(ClickableTreeView tv) : base()
        ...{
            ClickableTreeView clickable = tv as ClickableTreeView;
            if (clickable == null) throw new Exception("The clickable tree node was added to a non-clickable tree view");

            _parent = clickable;
            // register for the node clicked event, when *a* node gets clicked
            clickable.NodeClicked += new NodeClickedEvent(clickable_NodeClicked);
        }

        void clickable_NodeClicked(object sender, TreeNode nodeClicked)
        ...{
           // if the node is actually us, then fire the NodeClick event...
            if ((nodeClicked as ClickableTreeNode) == this)
            ...{              
                if (NodeClick != null)
                    NodeClick(this, new EventArgs());
            }              
        }
    }

    public class ClickableTreeView : TreeView
    ...{
        public event NodeClickedEvent NodeClicked;

        public ClickableTreeView() : base()
        ...{
            this.MouseClick += new MouseEventHandler(ClickableTreeView_MouseClick);
        }

        void ClickableTreeView_MouseClick(object sender, MouseEventArgs e)
        ...{
            TreeViewHitTestInfo inf = HitTest(e.X, e.Y);
            if (inf.Node == null) return; // didnt click a node...

            // we clicked a node, so notify that one was clicked...
            if (NodeClicked != null)
                NodeClicked(this, inf.Node);
            
        }       
    }
}

2、我们需要的是建立两个我们自己的类，分别实现IUIElementAdapterFactory和UIElementAdapter<T>。

 

 public class ClickableTreeViewAdapterFactory : IUIElementAdapterFactory
    ...{
        IUIElementManagerFactory Members#region IUIElementManagerFactory Members

        public IUIElementAdapter GetAdapter(object managedExtension)
        ...{
            if (managedExtension is ClickableTreeNode)
                return new ClickableTreeViewAdapter(managedExtension as ClickableTreeNode);
            else if (managedExtension is ClickableTreeView)
                return new ClickableTreeViewAdapter(managedExtension as ClickableTreeView);
            return null;
        }

        #endregion

        IUIElementAdapterFactory Members#region IUIElementAdapterFactory Members

        public bool Supports(object uiElement)
        ...{
            if (uiElement is ClickableTreeNode)
                return true;
            else if (uiElement is ClickableTreeView)
                return true;
            else
                return false;

        }

        #endregion
    }

 

 

 public class ClickableTreeViewAdapter: UIElementAdapter<ClickableTreeNode>
    ...{
        private ClickableTreeView _managed = null;
        private ClickableTreeNode _managedNode = null;
        public ClickableTreeViewAdapter(ClickableTreeView element)
        ...{
            _managed = element;
        }

        public ClickableTreeViewAdapter(ClickableTreeNode node)
        ...{
            _managedNode = node;
        }

        protected override void Remove(ClickableTreeNode uiElement)
        ...{
            if (_managed != null)
            ...{
                if (!_managed.IsDisposed)
                ...{
                    if (_managed.Nodes.Contains(uiElement))
                        _managed.Nodes.Remove(uiElement);
                }
            }
            else if (_managedNode != null)
            ...{
                if (!_managedNode.TreeView.IsDisposed)
                ...{
                    if (_managedNode.Nodes.Contains(uiElement))
                        _managedNode.Nodes.Remove(uiElement);
                }
            }
        }
    
        protected override ClickableTreeNode Add(ClickableTreeNode item)
        ...{
            if (_managed != null)
            ...{
                if (item.NeedsSetup)
                    item.SetUp(_managed);
                _managed.Nodes.Add(item);
            }
            else if (_managedNode != null)
            ...{
                if (item.NeedsSetup)
                    item.SetUp(_managedNode.TreeView);
                _managedNode.Nodes.Add(item);
            }

            return item;
        }        
    }

 

3、在初始化阶段注册我们自定义的界面工厂

 

        protected override void AfterShellCreated()
        ...{
            base.AfterShellCreated();

            IUIElementAdapterFactoryCatalog catalog = RootWorkItem.Services.Get<IUIElementAdapterFactoryCatalog>();
            catalog.RegisterFactory(new ClickableTreeViewAdapterFactory());

            // both main menus should have their items added to the root nodes collection
            RootWorkItem.UIExtensionSites.RegisterSite(UIExtensionConstants.MAINMENU, Shell.MainNavigationTree);

            // Load the menu structure from App.config
            UIElementBuilder.LoadFromConfig(RootWorkItem, Shell.MainNavigationTree);
        }