AjaxPro.NET框架生成高效率的Tree(Asp.net 2.0)(示例代码下载)

(一). 说明
        用Tree显示菜单及物品列表(从服务端获取数据)比较方便, 当前显示Tree 主要有两种方式:
        1. 在Tree初始化时将数据全部一次性从服务端获取, 获取完数据后页面展开或收缩时就不再需要获取数据,这样, 获取完数据使用时效率比较高, 但当树节点很多时, 在每次初始化时会有较大的延迟.
        2. 初始化时只加载展开的节点, 当用户需要查看某个节点下的数据时, 再去取数据, 这样, 初始化时延迟会相对减少, 但每次单击节点时要获取数据, 页面每次都要刷新, 所以也会产生延迟.
        此事例用Ajax实现第二种方式, 每次只动态加载要展开的节点数据(闭合节点不展开时,则不获取其子节点的数据),  另外加载节点时页面不会刷新.

(二). 运行示例图


(三). AjaxPro.NET简介

         首先对AjaxPro.NET作一下介绍, AjaxPro.NET是一个优秀的Ajax框架, 在实际应用中只要添加其DLL引用并进行简单的配置, 即可以非常方便的在客户端直接调用服务端方法, 来获取Tree节点.

(四).使用AjaxPro.NET预配置

  1. 添加 AjaxPro.dll 文件的引用(示例代码中已经包含,直接COPY过来使用即可).
   2. 在Web.config文件中添加以下配置

1 < httpHandlers >
2              < add verb = " POST,GET "  path = " ajaxpro/*.ashx "  type = " AjaxPro.AjaxHandlerFactory, AjaxPro "   />
3 </ httpHandlers >
4

 3. 在要使用AjaxPro.NET框架的页面 *.aspx.cs 的 Page_Load事件中加如下代码:

1 AjaxPro.Utility.RegisterTypeForAjax( typeof (_Default));

4. 经过以上三步骤后, 只要在后台服务端的方法前面增加属性[AjaxMethod]后:

 1 [AjaxMethod()]     //  or [AjaxPro.AjaxMethod] 
 2    public  ArrayList GetSearchItems(  string  strQuery )
 3    {
 4       //生成数据源
 5       ArrayList items = new ArrayList();
 6       items.Add("King");
 7       items.Add("Rose");
 8       return items ;
 9  }  
10

就可以在客户端直接使用服务端方法, 非常方便, 客户端调用后台代码如下:

var returnValue  =  后台代码类名.GetSearchItems(参数);

(五). 代码

         1. 页面 Tree.aspx 代码:

  1 <% @ Page Language = " C# "  AutoEventWireup = " true "   CodeFile = " Tree.aspx.cs "  Inherits = " _Default "   %>
  2  
  3   <! DOCTYPE html PUBLIC  " -//W3C//DTD XHTML 1.0 Transitional//EN "   " http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd " >
  4  
  5   < html xmlns = " http://www.w3.org/1999/xhtml "   >
  6   < head runat = " server " >
  7       < title > Ajax Efficient Tree </ title >
  8       < link type = " text/css "  href = " css/tree.css "  rel = " stylesheet " >
  9   </ head >
 10   < body >
 11       < form id = " form1 "  runat = " server " >
 12       < div >
 13           < asp:Panel ID = " Panel1 "  runat = " server "  Height = " 424px "  Width = " 251px " >
 14               < div id = " CategoryTree "   class = " TreeMenu " ></ div >
 15           </ asp:Panel >
 16           < script language = " jscript " >
 17              var tree  =  document.getElementById( " CategoryTree " );
 18              var root  =  document.createElement( " li " );
 19              root.id  =   " li_0 " ;
 20              tree.appendChild( root );
 21              ExpandSubCategory(  0  );
 22              function ExpandSubCategory( categoryID )
 23               {
 24                 var liFather = document.getElementById( "li_" + categoryID );
 25                 if( liFather.getElementsByTagName("li").length > 0)
 26                 {
 27                     ChangeStatus( categoryID );
 28                     return;
 29                 }
 30                 liFather.className = "Opened";
 31                 SwitchNode( categoryID, true );
 32                 
 33                 //仅获取当前节点的子Nodes
 34                 _Default.GetSubCategory( categoryID, GetSubCategory_callback );
 35             }             
 36              function SwitchNode( CategoryID, show )
 37               {
 38                 var li_father = document.getElementById("li_" + CategoryID);
 39                 if( show )
 40                 {
 41                     var ul = document.createElement("ul");
 42                     ul.id = "ul_note_" + CategoryID;
 43                     
 44                     var note = document.createElement("li");
 45                     note.className = "Child";              
 46                     
 47                     var img = document.createElement("img");
 48                     img.className = "s";
 49                     img.src = "css/s.gif";                    
 50                     
 51                     var a = document.createElement("a");
 52                     a.href = "javascript:void(0);";
 53                     a.innerHTML = "Please waiting";
 54                     
 55                     note.appendChild(img);
 56                     note.appendChild(a);
 57                     ul.appendChild(note);
 58                     li_father.appendChild(ul);                                        
 59                 }   
 60                 else
 61                 {
 62                     var ul = document.getElementById("ul_note_" + CategoryID );
 63                     if( ul )
 64                     {
 65                         li_father.removeChild(ul);
 66                     }
 67                 }             
 68             }
 69              function GetSubCategory_callback( response )
 70               {
 71                var dt = response.value.Tables[0];
 72                if( dt.Rows.length > 0 )
 73                {
 74                     var iCategoryID = dt.Rows[0].FatherID;               
 75                }                                
 76                var li_father = document.getElementById("li_" + iCategoryID );
 77                var ul = document.createElement("ul");
 78                for( var i = 0; i < dt.Rows.length; i++ )
 79                {
 80                     if( dt.Rows[i].IsChild == 1 )
 81                     {
 82                         var li = document.createElement("li");
 83                         li.className = "Child";
 84                         li.id = "li_" + dt.Rows[i].CategoryID;
 85                         var img = document.createElement("img");
 86                         img.id = dt.Rows[i].CategoryID;
 87                         img.className = "s";
 88                         img.src = "css/s.gif";
 89                         var a = document.createElement("a");
 90                         a.href = "javascript:OpenDocument('" + dt.Rows[i].CategoryID + "');";
 91                         a.innerHTML = dt.Rows[i].CategoryName;                                          
 92                     }
 93                     else
 94                     {
 95                         var li = document.createElement("li");
 96                         li.className = "Closed";
 97                         li.id = "li_" + dt.Rows[i].CategoryID;
 98                         var img = document.createElement("img");
 99                         img.id = dt.Rows[i].CategoryID;
100                         img.className = "s";
101                         img.src = "css/s.gif";
102                         img.onclick = function(){ ExpandSubCategory( this.id ); };
103                         img.alt = "Expand/collapse";
104                         var a = document.createElement("a");
105                         a.href = "javascript:ExpandSubCategory('" + dt.Rows[i].CategoryID + "');";
106                         a.innerHTML = dt.Rows[i].CategoryName;                                         
107                     }
108                     li.appendChild(img);
109                     li.appendChild(a);
110                     ul.appendChild(li);
111                }
112                li_father.appendChild(ul);
113                SwitchNode( iCategoryID, false );
114             }           
115              
116               // 单击叶节点时, 异步从服务端获取单个节点的数据.
117              function OpenDocument( CategoryID )
118               {                
119                 _Default.GetNameByCategoryID( CategoryID, GetNameByCategoryID_callback );
120             }
121              
122              function GetNameByCategoryID_callback( response )
123               {
124                 alert( response.value );
125             }
126              
127              function ChangeStatus( CategoryID )
128               {
129                 var li_father = document.getElementById("li_" + CategoryID );
130                 if( li_father.className == "Closed" )
131                 {
132                     li_father.className = "Opened";
133                 }
134                 else
135                 {
136                     li_father.className = "Closed";
137                 }
138            }               
139           </ script >           
140       </ div >
141       </ form >     
142   </ body >       
143   </ html >
144

2. 页面后台文件 Tree.aspx.cs 代码: 

  1 using  System;
  2   using  System.Data;
  3   using  System.Configuration;
  4   using  System.Web;
  5   using  System.Web.Security;
  6   using  System.Web.UI;
  7   using  System.Web.UI.WebControls;
  8   using  System.Web.UI.WebControls.WebParts;
  9   using  System.Web.UI.HtmlControls;
 10  
 11   public  partial  class  _Default : System.Web.UI.Page 
 12   {
 13    //此对象用于存放所有的节点数
 14    public static DataSet dsAllNodes = new DataSet();
 15 
 16    protected void Page_Load(object sender, EventArgs e)
 17    {
 18        AjaxPro.Utility.RegisterTypeForAjax(typeof(_Default));       
 19        CreateNodes();
 20    }
 21 
 22    private DataTable CreateStructure()
 23    {
 24       DataTable dt = new DataTable();
 25       dt.Columns.Add(new DataColumn("CategoryID", typeof(int)));
 26       dt.Columns.Add(new DataColumn("CategoryName", typeof(string)));
 27       dt.Columns.Add(new DataColumn("FatherID", typeof(string)));
 28       dt.Columns.Add(new DataColumn("IsChild", typeof(bool)));
 29       return dt;
 30    }
 31    public void CreateNodes()
 32    {
 33       DataTable dt = this.CreateStructure();
 34 
 35       DataRow drNew = dt.NewRow();
 36       drNew["CategoryID"] = 1;
 37       drNew["CategoryName"] = "物品类别";
 38       drNew["FatherID"] = 0;
 39       dt.Rows.Add( drNew );
 40 
 41       drNew = dt.NewRow();
 42       drNew["CategoryID"] = 2;
 43       drNew["CategoryName"] = "水果";
 44       drNew["FatherID"] = 1;
 45       dt.Rows.Add( drNew );
 46 
 47       drNew = dt.NewRow();
 48       drNew["CategoryID"] = 3;
 49       drNew["CategoryName"] = "工具";
 50       drNew["FatherID"] = 1;
 51       dt.Rows.Add( drNew );
 52 
 53       drNew = dt.NewRow();
 54       drNew["CategoryID"] = 4;
 55       drNew["CategoryName"] = "萍果";
 56       drNew["FatherID"] = 2;
 57       dt.Rows.Add( drNew );
 58 
 59       drNew = dt.NewRow();
 60       drNew["CategoryID"] = 5;
 61       drNew["CategoryName"] = "香蕉";
 62       drNew["FatherID"] = 2;
 63       dt.Rows.Add( drNew );
 64 
 65       drNew = dt.NewRow();
 66       drNew["CategoryID"] = 6;
 67       drNew["CategoryName"] = "桔子";
 68       drNew["FatherID"] = 2;
 69       dt.Rows.Add( drNew );
 70 
 71       drNew = dt.NewRow();
 72       drNew["CategoryID"] = 7;
 73       drNew["CategoryName"] = "萝卜";
 74       drNew["FatherID"] = 2;
 75       dt.Rows.Add( drNew );
 76 
 77       drNew = dt.NewRow();
 78       drNew["CategoryID"] = 8;
 79       drNew["CategoryName"] = "钢笔";
 80       drNew["FatherID"] = 3;
 81       dt.Rows.Add( drNew );
 82 
 83       drNew = dt.NewRow();
 84       drNew["CategoryID"] = 9;
 85       drNew["CategoryName"] = "铅笔";
 86       drNew["FatherID"] = 3;
 87       dt.Rows.Add( drNew );
 88 
 89       drNew = dt.NewRow();
 90       drNew["CategoryID"] = 10;
 91       drNew["CategoryName"] = "尺子";
 92       drNew["FatherID"] = 3;
 93       dt.Rows.Add( drNew );
 94       
 95       drNew = dt.NewRow();
 96       drNew["CategoryID"] = 11;
 97       drNew["CategoryName"] = "橡皮";
 98       drNew["FatherID"] = 3;
 99       dt.Rows.Add( drNew );
100 
101       dsAllNodes.Tables.Add(dt);
102    }
103 
104    [AjaxPro.AjaxMethod]
105    public DataSet GetSubCategory(int CategoryID)
106    {
107       DataSet ds = new DataSet();
108       DataTable dt = this.CreateStructure();
109       DataRow[] drSelect = dsAllNodes.Tables[0].Select("FatherID=" + CategoryID.ToString());
110       foreach (DataRow drTemp in drSelect)
111       {
112          DataRow dr = dt.NewRow();
113          dr["CategoryID"] = drTemp["CategoryID"];
114          dr["CategoryName"] = drTemp["CategoryName"];
115          dr["FatherID"] = drTemp["FatherID"];
116          dr["IsChild"] = IsLeaf( int.Parse( drTemp["CategoryID"].ToString() ) );
117          dt.Rows.Add(dr);
118       }
119       ds.Tables.Add(dt);
120       return ds;
121    }
122 
123    [AjaxPro.AjaxMethod]
124    public bool IsLeaf(int Category)
125    {
126        foreach(DataRow dr in dsAllNodes.Tables[0].Rows)
127        {
128           if (dr["FatherID"] != null && int.Parse(dr["FatherID"].ToString()) == Category)
129           {
130              return false;  
131           }
132        }
133        return true;
134    }
135 
136    [AjaxPro.AjaxMethod]
137    public string GetNameByCategoryID(string CategoryID )
138    {
139       foreach( DataRow dr in dsAllNodes.Tables[0].Rows )
140       {
141          if( dr["CategoryID"].ToString() == CategoryID.ToString() )
142          {
143             return dr["CategoryName"].ToString();
144          }
145       }
146       return "";
147    }
148 }