学步园

演示示例为一个学生信息查看菜单：先选择部门，再选择班级，最后选择学生姓名，查看学生信息；

效果图：

 

 

采用TreeView的SelectedNodeChanged事件作为一个包含用来显示学生信息的Lable的UpdatePanel的触发器，如下：

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<form id="form1" runat="server"><br /> <div><br /> <asp:ScriptManager ID="ScriptManager1" runat="server"><br /> </asp:ScriptManager><br /> <asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional"><br /> <ContentTemplate><br /> <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label><br /> </ContentTemplate><br /> <Triggers><br /> <asp:AsyncPostBackTrigger ControlID="TreeView1"<br /> EventName="SelectedNodeChanged" /><br /> </Triggers><br /> </asp:UpdatePanel><br /> <asp:TreeView ID="TreeView1" runat="server"<br /> onselectednodechanged="TreeView1_SelectedNodeChanged"<br /> ontreenodepopulate="TreeView1_TreeNodePopulate" Width="169px"<br /> ExpandDepth="0" ShowLines="True"><br /> <Nodes><br /> <asp:TreeNode Text="部门->班级->学生" SelectAction="Expand" PopulateOnDemand="true" Value="请选择"></asp:TreeNode><br /> </Nodes><br /> </asp:TreeView></p> <p> </div><br /> </form>

 

其中一些涉及数据库的查询，采用LINQ的写法，再此不多作说明，其先决条件：在“服务器资源管理器”中添加连接，选择数据库，右击“解决方案资源管理器”，选择“添加新项”，选择“LINQ to sql类”，将你需要用的表从“服务器资源管理器”拖入跳出的界面中，一定要保存，好了，完整代码如下：

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using System;<br /> using System.Configuration;<br /> using System.Data;<br /> using System.Linq;<br /> using System.Web;<br /> using System.Web.Security;<br /> using System.Web.UI;<br /> using System.Web.UI.HtmlControls;<br /> using System.Web.UI.WebControls;<br /> using System.Web.UI.WebControls.WebParts;<br /> using System.Xml.Linq;<br /> using System.Text;//StringBuilder所在命名空间</p> <p>public partial class _Default : System.Web.UI.Page<br /> {<br /> protected void Page_Load(object sender, EventArgs e)<br /> {</p> <p> }</p> <p> protected void TreeView1_SelectedNodeChanged(object sender, EventArgs e)<br /> {<br /> JWInfoDataContext db = new JWInfoDataContext();</p> <p> //LNNQ写法<br /> var result = (from stuIn in db.学生信息<br /> where stuIn.学号.ToString() == this.TreeView1.SelectedNode.Value.ToString()<br /> select stuIn).First();<br /> if (result != null)<br /> {<br /> StringBuilder strStuInfo = new StringBuilder();<br /> strStuInfo.AppendLine("学号：" + result.学号.ToString());<br /> strStuInfo.AppendLine("<br />姓名：" + result.姓名.ToString());<br /> strStuInfo.AppendLine("<br />性别：" + result.性别.ToString());<br /> strStuInfo.AppendLine("<br />班级编号：" + result.班级编号.ToString());<br /> Label1.Text = strStuInfo.ToString();<br /> }<br /> else<br /> {<br /> Label1.Text = "没有数据！";<br /> }<br /> }</p> <p> protected void TreeView1_TreeNodePopulate(object sender, TreeNodeEventArgs e)<br /> {<br /> //获取根节点深度，****注意***设置TreeView的ExpandDepth="0"，即默认根节点深度为0<br /> switch (e.Node.Depth)<br /> {<br /> case 0://填充一级节点<br /> PopulateDept(e.Node);<br /> break;<br /> case 1://填充二级节点<br /> PopulateClassID(e.Node);<br /> break;<br /> case 2://三级<br /> PopulateStu(e.Node);<br /> break;<br /> default:<br /> break;<br /> }<br /> }</p> <p> /// <summary><br /> /// 填充一级节点的代码<br /> /// </summary><br /> /// <param name="node"></param><br /> private void PopulateDept(TreeNode node)<br /> {<br /> DataTable dt = RunQuery("PopulateDept", null);</p> <p> if (dt.Rows.Count > 0)<br /> {<br /> foreach (DataRow row in dt.Rows)<br /> {<br /> //创建一级节点<br /> TreeNode newNode = new TreeNode();<br /> newNode.Text = row["部门名称"].ToString();<br /> newNode.Value = row["部门编号"].ToString();</p> <p> //指示为动态填充节点<br /> newNode.PopulateOnDemand = true;</p> <p> //设置选择节点时激发TreeNodeExpanded 事件<br /> newNode.SelectAction = TreeNodeSelectAction.Expand;</p> <p> //将子节点加入父节点中<br /> node.ChildNodes.Add(newNode);<br /> }<br /> }<br /> }</p> <p> /// <summary><br /> /// 填充二级节点<br /> /// </summary><br /> /// <param name="node"></param><br /> private void PopulateClassID(TreeNode node)<br /> {<br /> DataTable dt = RunQuery("PopulateClassID", node.Value);</p> <p> if (dt.Rows.Count > 0)<br /> {<br /> foreach (DataRow row in dt.Rows)<br /> {<br /> TreeNode newNode = new TreeNode();<br /> newNode.Text = row["班级名称"].ToString();<br /> newNode.Value = row["班级编号"].ToString();</p> <p> newNode.PopulateOnDemand = true;</p> <p> newNode.SelectAction = TreeNodeSelectAction.Expand;</p> <p> node.ChildNodes.Add(newNode);<br /> }<br /> }<br /> }</p> <p> /// <summary><br /> /// 填充末节点(学生列表)<br /> /// </summary><br /> /// <param name="node"></param><br /> private void PopulateStu(TreeNode node)<br /> {<br /> DataTable dt = RunQuery("PopulateStu", node.Value);</p> <p> if (dt.Rows.Count > 0)<br /> {<br /> foreach (DataRow row in dt.Rows)<br /> {<br /> TreeNode newNode = new TreeNode();<br /> newNode.Text = row["姓名"].ToString();<br /> newNode.Value = row["学号"].ToString();</p> <p> //不设置动态填充节点<br /> newNode.PopulateOnDemand = false;</p> <p> //设置选择该级节点时引发 SelectedNodeChanged 事件<br /> newNode.SelectAction = TreeNodeSelectAction.Select;</p> <p> node.ChildNodes.Add(newNode);<br /> }<br /> }<br /> }</p> <p> /// <summary><br /> /// 取得节点信息<br /> /// </summary><br /> /// <param name="QueryString">填充节点等级说明</param><br /> /// <param name="nodeValue">筛选条件</param><br /> /// <returns>查询结果</returns><br /> private DataTable RunQuery(string QueryString, string nodeValue)<br /> {<br /> DataTable mytable = new DataTable();</p> <p> if (QueryString == "PopulateDept")<br /> {<br /> mytable.Columns.Add("部门编号", typeof(string));<br /> mytable.Columns.Add("部门名称", typeof(string));</p> <p> //LINQ实体操作类，生成的<br /> JWInfoDataContext db = new JWInfoDataContext();</p> <p> var result = from dept in db.部门<br /> select new { dept.部门编号, dept.部门名称 };</p> <p> foreach (var item in result)<br /> {<br /> DataRow newRow = mytable.NewRow();<br /> newRow["部门编号"] = item.部门编号.ToString();<br /> newRow["部门名称"] = item.部门名称.ToString();<br /> mytable.Rows.Add(newRow);<br /> }<br /> }<br /> else if (QueryString == "PopulateClassID")<br /> {<br /> mytable.Columns.Add("班级编号", typeof(string));<br /> mytable.Columns.Add("班级名称", typeof(string));</p> <p> JWInfoDataContext db = new JWInfoDataContext();<br /> var reuslt = from Class in db.班级<br /> where Class.部门编号 == nodeValue<br /> select new { Class.班级编号, Class.班级名称 };</p> <p> foreach (var item in reuslt)<br /> {<br /> DataRow row = mytable.NewRow();<br /> row["班级编号"] = item.班级编号.ToString();<br /> row["班级名称"] = item.班级名称.ToString();<br /> mytable.Rows.Add(row);<br /> }<br /> }</p> <p> else if (QueryString == "PopulateStu")<br /> {<br /> mytable.Columns.Add("学号", typeof(string));<br /> mytable.Columns.Add("姓名", typeof(string));</p> <p> JWInfoDataContext db = new JWInfoDataContext();</p> <p> var result = from stu in db.学生信息<br /> where stu.班级编号 == nodeValue<br /> select new { stu.学号, stu.姓名 };</p> <p> foreach (var item in result)<br /> {<br /> DataRow row = mytable.NewRow();<br /> row["学号"] = item.学号.ToString();<br /> row["姓名"] = item.姓名.ToString();<br /> mytable.Rows.Add(row);<br /> }<br /> }<br /> return mytable;<br /> }<br /> }<br />