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

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            ArrayList list2 = ReadSomeInts();
            int Sum = 0;
            foreach (object obj in list2)
            {
                int Ivalue = Convert.ToInt32(obj);
                Sum = Sum + Ivalue;
            }

            Console.WriteLine("Sum={0}",Sum);
            Console.ReadKey();
        }
        static ArrayList ReadSomeInts()
        {
            ArrayList list1 = new ArrayList();
                                                            
            for (int i = 0; i < 3; i++)
            {
                string str = Console.ReadLine();
                int iValue = Convert.ToInt32(str);
                list1.Add(iValue);
            }
            return list1;
 
        }

    }
}



我想请问下  foreach循环
            foreach (object obj in list2)
            {
                int Ivalue = Convert.ToInt32(obj);
                Sum = Sum + Ivalue;
            }
老是提示：“运算符“+”无法应用于“object”和“int”类型的操作数”这个错误代码  
int Ivalue = Convert.ToInt32(obj);
int Ivalue=(int)obj;
这两种都不可以，麻烦各位前辈稍稍指点下，谢谢了哈


            foreach (object obj in list3)
            {
                Console.WriteLine("{0}",obj);
            }
这样就可以，这里的obj是当做一个对象处理的吗？


晕，我再打开 ，试一下。竟然可以了，没编程天赋啊，嗨。看一会头就晕

[ 本帖最后由 solonight 于 2010-8-8 23:58 编辑 ]

以上程序是对的，list2里的数据必须是数字，这样才能转换，才能相加