1http://www.cnblogs.com/Images/OutliningIndicators/ContractedBlock.gif/// <summary> 
 2http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif/// 绑定生成一个有树结构的下拉菜单 
 3http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif/// </summary> 
 4http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif/// <param name="dtNodeSets">菜单记录数据所在的表</param> 
 5http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif/// <param name="strParentColumn">表中用于标记父记录的字段</param> 
 6http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif/// <param name="strRootValue">第一层记录的父记录值(通常设计为0或者-1或者Null)用来表示没有父记录</param> 
 7http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif/// <param name="strIndexColumn">索引字段，也就是放在DropDownList的Value里面的字段</param> 
 8http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif/// <param name="strTextColumn">显示文本字段，也就是放在DropDownList的Text里面的字段</param> 
 9http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif/// <param name="drpBind">需要绑定的DropDownList</param> 
10http://www.cnblogs.com/Images/OutliningIndicators/ExpandedBlockEnd.gif/// <param name="i">用来控制缩入量的值，请输入-1</param> 
11http://www.cnblogs.com/Images/OutliningIndicators/None.gifprivate void MakeTree(DataTable dtNodeSets,string strParentColumn,

                      string strRootValue,string strIndexColumn,

                      string strTextColumn,DropDownList drpBind,int i) 
12{ 
13http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    //每向下一层，多一个缩入单位 
14http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    i++; 
15http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif
16http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    DataView dvNodeSets = new DataView(dtNodeSets); 
17http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    dvNodeSets.RowFilter = strParentColumn + "=" + strRootValue; 
18http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif
19http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    string strPading = ""; //缩入字符 
20http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif
21http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    //通过i来控制缩入字符的长度，我这里设定的是一个全角的空格 
22http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    for(j=0;j<i;j++) 
23http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif        strPading += "　";//如果要增加缩入的长度，改成两个全角的空格就可以了 
24http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif
25http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    foreach(DataRowView drv in dvNodeSets) 
26http://www.cnblogs.com/Images/OutliningIndicators/ContractedSubBlock.gif  { 
27http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif        ListItem li = new ListItem(strPading + "├" + drv[strTextColumn].ToString(),drv[strIndexColumn].ToString()); 
28http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif        drpBind.Items.Add(li); 
29http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif        MakeTree(dtNodeSets,strParentColumn,drv[strIndexColumn].ToString(),strIndexColumn,strTextColumn,drpBind,i); 
30http://www.cnblogs.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif    } 
31http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif
32http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    //递归结束，要回到上一层，所以缩入量减少一个单位 
33http://www.cnblogs.com/Images/OutliningIndicators/InBlock.gif    i--; 
34http://www.cnblogs.com/Images/OutliningIndicators/ExpandedBlockEnd.gif}