泛型

using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Text;
using System.Reflection;
 
namespace Extension
{
 
    public static class Extension
    {
        public static IList<T> ToList<T>(this DataTable dt)
        {
            var lst = new List<T>();
            var plist = new List<System.Reflection.PropertyInfo>(typeof(T).GetProperties());
            foreach (DataRow item in dt.Rows)
            {
                T t = System.Activator.CreateInstance<T>();
                for (int i = 0; i < dt.Columns.Count; i++)
                {
                    PropertyInfo info = plist.Find(p => p.Name == dt.Columns[i].ColumnName);
                    if (info != null)
                    {
                        if (!Convert.IsDBNull(item[i]))
                        {
                            info.SetValue(t, item[i], null);
                        }
                    }
                }<br>                lst.Add(t);
            }
            return lst;
            ///throw new NotImplementedException();
        }
 
    }
}

using System;
using System.Text;
using System.Reflection;
using System.Collections;
using System.Collections.Generic;

namespace ConsoleApplication1
{
    public class Node
    {
        private int _id;
        private int _pid;
        private string _name;

        public Node() { }

        public Node(int id, int pid, string name)
        {
            _id = id;
            _pid = pid;
            _name = name;
        }

        public int ID
        {
            get { return _id; }
            set { _id = value; }
        }

        public int PID
        {
            get { return _pid; }
            set { _pid = value; }
        }

        public string Name
        {
            get { return _name; }
            set { _name = value; }
        }

        public override string ToString()
        {
            return "ID:" + _id + "\t" + "PID:" + _pid + "\t" + "Name:" + _name;
        }
    }

    class B
    {
        private object _dataSource;
        public object DataSource
        {
            get { return _dataSource; }
            set { _dataSource = value; }
        }

        //怎么遍历DataSource，取出ID,PID,Name属性值？
         public void RecursionList()
        {
            if (this._dataSource == null) return;
            if (this._dataSource is IEnumerable)
            {
               IEnumerable nodeList = (IEnumerable)this._dataSource;
               foreach (object node in nodeList)
               {
                 PropertyInfo[] props = node.GetType().GetProperties();
                 foreach (System.Reflection.PropertyInfo prop in props)
                 {
                    object propValue = prop.GetValue(node, null);
                    Console.WriteLine(string.Format("{0} = {1}", prop.Name, propValue));
                 }
               }
            } 
            else if (this._dataSource is IEnumerable)//其他类型呢?
            {
              ... 此时,你想到什么呢?什么要做可使扩展性更好呢?
            }
        }
    }

    //应用举例
    class Program
    {
        static void Main(string[] args)
        {
            List<Node> listTree = new List<Node>();
            listTree.Add(new Node(0, 1, "北京"));
            listTree.Add(new Node(1, -1, "中国"));
            listTree.Add(new Node(2, 6, "莫斯科"));
            listTree.Add(new Node(3, 0, "海淀区"));
            listTree.Add(new Node(4, 0, "朝阳区"));
            listTree.Add(new Node(5, 3, "上地"));
            listTree.Add(new Node(6, -1, "俄罗斯"));
            listTree.Add(new Node(8, -1, "美国"));

            B newB = new B();
            newB.DataSource = listTree;
            newB.RecursionList();

            Console.Read();
        }
    }
}