Coolite Toolkit学习笔记七：常用控件TreePanel

 

      Coolite Toolkit中的Tree控件和Menu控件一样不能独立使用，他们必须依托与容器控件，理所当然Tree控件就依托于TreePanel 控件了。TreePanel 提供了很多的集合属性，可用来定制非常丰富的切功能强大的树型界面。
                  
      从上图中可看出，TreePanel提供了许多的集合属性，包括事件、数据加载、按扭、自定义配置、根节点、工具栏、顶部和底部工具栏等等很多功能点。比如我们可以使用TopBar来定制一个树的顶部工具栏，如下代码片段：

<ext:TreePanel ID="tPanel" runat="server" Height="300" Title="树控件学习" 
    Icon="BookOpen" Width="180">
    <TopBar>
        <ext:Toolbar runat="server">
            <Items>
                <ext:Button runat="server" Text="全部展开" Icon="ArrowOut">
                    <Listeners>
                        <Click Handler="#{tPanel}.expandAll();" />
                    </Listeners>
                </ext:Button>
                <ext:Button runat="server" Text="全部折叠" Icon="ArrowIn">
                    <Listeners>
                        <Click Handler="#{tPanel}.collapseAll();" />
                    </Listeners>
                </ext:Button>
            </Items>
        </ext:Toolbar>
    </TopBar>
</ext:TreePanel>

      
      如上通过html标签的方式使用TreePanel的TopBar定义好了一个树的顶部工具栏，并实现了其单击的客户端事件，通过点击相应的按扭可实现树的折叠和展开功能。  树通常都是有根节点的，我们可以使用Root属性来定义树的根节点，在一棵树中，其根其实也是一个节点，根下的有子节点集合和子节点等这样的类型结构，如下定义了一个根节点下有多个子节点的示例：

<ext:TreePanel ID="tPanel" runat="server" Height="300" Title="树控件学习" 
    Icon="BookOpen" Width="180">
    <TopBar>
        <ext:Toolbar runat="server">
            <Items>
                <ext:Button runat="server" Text="全部展开" Icon="ArrowOut">
                    <Listeners>
                        <Click Handler="#{tPanel}.expandAll();" />
                    </Listeners>
                </ext:Button>
                <ext:Button runat="server" Text="全部折叠" Icon="ArrowIn">
                    <Listeners>
                        <Click Handler="#{tPanel}.collapseAll();" />
                    </Listeners>
                </ext:Button>
            </Items>
        </ext:Toolbar>
    </TopBar>
    <Root>
        <ext:TreeNode Text="歌曲列表" Expandable="True">
            <Nodes>
                <ext:TreeNode Text="一生有你" Icon="Music" />
                <ext:TreeNode Text="擦肩而过" Icon="Music" />
                <ext:TreeNode Text="寂寞在唱歌" Icon="Music" />
                <ext:TreeNode Text="等一分钟" Icon="Music" />
                <ext:TreeNode Text="依然在一起" Icon="Music" />
            </Nodes>
        </ext:TreeNode>
    </Root>
</ext:TreePanel>

                            
      针对上图的示例，来扩充一下需求，根据歌曲演唱者对歌曲进行归类，从树的结构上来分析则是歌曲演唱者是歌曲列表下的子节点，歌曲是歌曲演唱者下的子节点。那么是下面这样的吗？

<ext:TreePanel ID="tPanel" runat="server" Height="300" Title="树控件学习" 
    Icon="BookOpen" Width="180">
    <TopBar>
        <ext:Toolbar runat="server">
            <Items>
                <ext:Button runat="server" Text="全部展开" Icon="ArrowOut">
                    <Listeners>
                        <Click Handler="#{tPanel}.expandAll();" />
                    </Listeners>
                </ext:Button>
                <ext:Button runat="server" Text="全部折叠" Icon="ArrowIn">
                    <Listeners>
                        <Click Handler="#{tPanel}.collapseAll();" />
                    </Listeners>
                </ext:Button>
            </Items>
        </ext:Toolbar>
    </TopBar>
    <Root>
        <ext:TreeNode Text="歌曲列表" Expandable="True" Icon="Cd">
            <Nodes>
                <ext:TreeNode Text="水木年华" Icon="Music">
                    <Nodes>
                        <ext:TreeNode Text="一生有你" Icon="ControlPlay" />
                        <ext:TreeNode Text="完美世界" Icon="ControlPlay" />
                    </Nodes>
                </ext:TreeNode>
                <ext:TreeNode Text="宇桐非" Icon="Music">
                    <Nodes>
                        <ext:TreeNode Text="擦肩而过" Icon="ControlPlay" />
                        <ext:TreeNode Text="不要放弃" Icon="ControlPlay" />
                    </Nodes>
                </ext:TreeNode>
                <ext:TreeNode Text="寂寞在唱歌" Icon="Music">
                    <Nodes>
                        <ext:TreeNode Text="阿桑" Icon="ControlPlay" />
                    </Nodes>
                </ext:TreeNode>
                <ext:TreeNode Text="徐誉滕" Icon="Music">
                    <Nodes>
                        <ext:TreeNode Text="等一分钟" Icon="ControlPlay" />
                    </Nodes>
                </ext:TreeNode>
                <ext:TreeNode Text="马天宇" Icon="Music">
                    <Nodes>
                        <ext:TreeNode Text="依然在一起" Icon="ControlPlay" />
                    </Nodes>
                </ext:TreeNode>
            </Nodes>
        </ext:TreeNode>
    </Root>
</ext:TreePanel>

                        

      除了构建树结果外，平时项目开发中重要的是使用结构里的数据，那Coolite Toolkit的TreePanel里的树节点我们可以通过什么方式得到里面的数据呢，其实这一部非常简单，在本文前面我曾提到过，树是又不同的节点(Node)组成，那么取值也是通过节点就OK了。可以通过控件的Listeners属性给控件注册一个事件，通过事件来获取所点击项的值，如下图：      
                        

注：此文章转载至Bēniaǒ成长笔记