引用型別和值型別

背景：當一個變數以引數形式傳入函式的時候，在函式進行操作後。該值改變了嗎？

基礎：引用型別和值型別；作用域；靜態函式；

答案及原理：

當引數為值型別的時候，傳入函式的是值而不是地址。該函式會自己建立一份記憶體來儲存這份值。所以無論函式內如何操作，函式外的值是永遠不會變的。

當引數為引用型別的時候，傳入函式的是地址。該函式內所有操作都是對地址所指向的記憶體單元進行才做。SO，函式內的操作會影響函式外的一切。

程式碼演示：

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

namespace RefValTest
{
    //班級
    public class Class {
        //班級名稱
        public string className { get; set; }
        //班級編號
        public string classCode { get; set; }
        public Class(string className ,string classCode){
            this.classCode = classCode;
            this.className = className;
    }
    }
    class Program
    {
        public static Class staticClass = new Class("源動力_Static", "007_Static");
        public static Class staticClass1 = new Class("源動力_Static", "007_Static");
        /// <summary>
        /// 測試引用型別和值型別
        /// </summary>
        /// <param name="args"></param>
        static void Main(string[] args)
        {
            //值型別
            int i = 0;
            //引用型別
            Class yuanDongLi = new Class("源動力_Common", "007_Common");
            Class yuanDongLi1 = new Class("源動力_Common", "007_Common");
            //普通呼叫
            ChangeVlaue(i, yuanDongLi, staticClass);
            Console.WriteLine("i:" + i + "   yuanDongLi:" + yuanDongLi.className + "   staticClass：" + staticClass.className);
            //ref out 引用
            int j;
            ChangeVlaue(ref i,out j, ref yuanDongLi1, out staticClass1);
            Console.WriteLine("i:" + i + "   yuanDongLi:" + yuanDongLi.className + "   staticClass：" + staticClass.className+"   j:"+j);
        }
        /// <summary>
        /// 普通方法
        /// </summary>
        /// <param name="i"></param>
        /// <param name="yuanDongLi"></param>
        /// <returns></returns>
        public static void ChangeVlaue(int i, Class yuanDongLi, Class staticClass)
        {
            i = i + 1;
            yuanDongLi.classCode += "_Change";
            yuanDongLi.className += "_Change";
            staticClass.classCode += "_Change";
            staticClass.className += "_Change";
          
        }

        /// <summary>
        /// ref out 引靜態變數
        /// </summary>
        /// <param name="i"></param>
        /// <param name="yuanDongLi"></param>
        /// <returns></returns>
        public static void ChangeVlaue(ref int i,out int j, ref Class yuanDongLi, out Class tempClass)
        {
            j = i;
            i = i + 1;
            j = j + 1;
            yuanDongLi.classCode += "_Change";
            yuanDongLi.className += "_Change";
            tempClass = staticClass1;
            tempClass.classCode += "_Change";
            tempClass.className += "_Change";    
        }
    }
}