Tree

用Asp.net 写的一个通用的Tree

 

using System;
using System.Data;
using MyOA.DataAccessLayer;

namespace MyOA.CommonComponent
...{
    /**//// <summary>
    /// 一个通用的树状菜单类
    /// </summary>
    public class Tree
    ...{
        private string _treeHtml;
        private DataTable _dataTable;

        /**//// <summary>
        /// 根据DataTable对象，生成一棵树
        /// </summary>
        /// <param name="dataTable">树中节点的数据</param>
        /// <returns>树的HTML代码</returns>
        public string CreateTree(DataTable dataTable)
        ...{
            this._dataTable=dataTable;
            this.CreateSubTree(0);
            return _treeHtml;    
        }

        /**//// <summary>
        /// 获取父节点编号为parentId的所有节点，并用DataTable返回
        /// </summary>
        /// <param name="parentId">父节点编号</param>
        /// <returns>DataTable形式的所有孩子节点数据</returns>
        private DataTable GetChilds(int parentId)
        ...{
            DataTable childNodes=new DataTable();
            childNodes=this._dataTable.Clone();

            foreach(DataRow dr in this._dataTable.Rows)
            ...{
                if(Convert.ToInt32(dr["ParentId"])==parentId)
                ...{
                    childNodes.ImportRow(dr);
                }
            }

            return childNodes;
        }

        /**//// <summary>
        /// 判断编号为nodeId的节点是否为叶子节点
        /// </summary>
        /// <param name="nodeId">待判断的节点编号</param>
        /// <returns>是叶子节点：返回true；否则：返回false</returns>
        private bool IsLeaf(int nodeId)
        ...{
            foreach(DataRow dr in this._dataTable.Rows)
                if(Convert.ToInt32(dr["ParentId"])==nodeId)
                    return false;
            return true;
        }

        /**//// <summary>
        /// 得到编号为nodeId的节点的父节点编号
        /// </summary>
        /// <param name="nodeId">节点编号</param>
        /// <returns>父节点编号</returns>
        private int GetParent(int nodeId)
        ...{
            foreach(DataRow dr in this._dataTable.Rows)
                if(Convert.ToInt32(dr["NodeId"])==nodeId)
                    return Convert.ToInt32(dr["ParentId"]);
            return -1;
            
        }

        /**//// <summary>
        /// 得到编号为nodeId的节点的级别，根节点为0
        /// </summary>
        /// <param name="nodeId">待计算的巨额电编号</param>
        /// <returns>节点的级别，根节点为0</returns>
        private int GetLevel(int nodeId)
        ...{
            int parentId=GetParent(nodeId);
            if(parentId==0) return 1;
            else
                return GetLevel(parentId)+1;    //递归
        }
        
        /**//// <summary>
        /// 递归生成根编号为nodeId的树
        /// </summary>
        /// <param name="nodeId">所要生成子树的根节点</param>
        private void CreateSubTree(int nodeId)
        ...{
            DataTable childNodes=this.GetChilds(nodeId);    //获取根节点的所有孩子

            //循环生成根节点的所有孩子对应的HTML
            int childId=0;
            foreach(DataRow dr in childNodes.Rows)
            ...{
                childId=Convert.ToInt32 (dr["nodeId"]);
                this._treeHtml+="<div id=div_"+childId.ToString()+">";

                //根据该孩子的级别，生成一些空格，以体现层次结构
                for(int i=0;i<GetLevel(childId);i++)
                    this._treeHtml+="&nbsp;&nbsp;";

                //如果该孩子是叶子节点，则生成其HTML代码
                if(this.IsLeaf(childId))
                ...{
                    this._treeHtml+="<img src='./Images/folder.gif'/><a href="+dr["Url"]+">"+dr["Text"]+"</a></div>";
                }
                //如果该孩子为中间节点，则首先构造其HTML，然后递归生成其所有孩子的HTML
                else
                ...{
                    this._treeHtml+="<img src='./Images/folderopen.gif'/><a href="+dr["Url"]+">"+dr["Text"]+"</a></div>";
                    this.CreateSubTree(childId);//递归
                }
            }
        }
    }
}