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

namespace Test
{
    static class Program
    {
        static void Main(string[] args)
        {
            DataTable x = null;
            x.NotNull();//在这加了断点跟踪,经过下边的扩展方法后,仍然为null,可是DataTable是按引用传的啊,实在想不通,请问这是为什么啊?
            Console.Read();
        }
        static public void NotNull(this DataTable dt)
        {
            if (dt == null)
            {
                dt = new DataTable();
            }
        }

    }
}

public static void NotNull(this DataTable dt, ref DataTable dtSrc)
        {
            if (dtSrc == null)
            {
                dtSrc = new DataTable();
            }
        }