Expression 常用方法

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Linq.Expressions;
using System.Collections;
using System.Data.Common;
using System.Data;
using System.Data.Linq;
using System.Reflection;
using System.Diagnostics;

namespace ConsoleApp
{

    public class Boy
    {
        public int UserID;
        public int Age;
        public string Name;
        public static string Move()
        {
            return string.Format("The Boy begin Move;");
        }

        public static int GetDoubbleNum(int num)
        {
            return num + num;
        }
        public Boy() { }


        public string Play(string objName)
        {
            return "Play the "+objName;
        }
    }



    class Program
    {
        static void Main(string[] args)
        {
            ParameterExpression boyParameter = Expression.Parameter(typeof(Boy), "boy");
            ParameterExpression intParameter = Expression.Parameter(typeof(Int32), "i");
            ParameterExpression strParameter = Expression.Parameter(typeof(string), "str");
            // 调用无参静态方法
            MethodInfo mInfo = typeof(Boy).GetMethod("Move");
            MethodCallExpression mcExp = Expression.Call(null,  // 静态方法为null
                mInfo,
                new Expression[] { }  // 静态方法 传入的参数类型 typeof(object)
                );
            var staticMethodNoPrameter = Expression.Lambda<Func<Boy, string>>(mcExp, boyParameter).Compile();


            // 调用有参静态方法
            mInfo = typeof(Boy).GetMethod("GetDoubbleNum");
            mcExp = Expression.Call(null,
                mInfo, 
                new Expression[] { intParameter});
            var staticMethodHavePrameter = Expression.Lambda<Func<Boy,int, int>>(mcExp, boyParameter,intParameter).Compile();


            // 调用普通方法
            mInfo = typeof(Boy).GetMethod("Play");
            mcExp = Expression.Call(boyParameter,
                mInfo,
                new Expression[] { strParameter });
            var generalMethod = Expression.Lambda<Func<Boy, string, string>>(mcExp, boyParameter, strParameter).Compile();


            Boy boy = new Boy() { UserID = 10, Age = 18, Name = "Rhythmk" };

            Console.WriteLine("staticMethodNoPrameter:" + staticMethodNoPrameter(boy));
            Console.WriteLine("staticMethodHavePrameter:" + staticMethodHavePrameter(boy,12));
            Console.WriteLine("generalMethod:" + generalMethod(boy, "FootBoy"));

            /*  输出结果：
             * staticMethodNoPrameter:The Boy begin Move;
             * staticMethodHavePrameter:24
             * generalMethod:Play the FootBoy
             */

            Console.Read();
        }



    }

}