C# 的各种小实验

List<> 的 Count

using System;
using System.Collections.Generic;

namespace ListTest
{
    class Program
    {
        static void Main(string[] args)
        {
            List<int> list = new List<int>(5);
            Console.WriteLine(list.Count);
        }
    }
}

结果为 0

using System;
using System.Collections.Generic;

namespace ListTest
{
    class Program
    {
        static void Main(string[] args)
        {
            List<int> list = new List<int>(5);
            list.Add(1);
            Console.WriteLine(list.Count);
        }
    }
}

结果为 1
结论：初始化的时候开几个内存都不重要~

struct 、class、dictionary

    private class OneInfomation
    {
        public bool isDirty;
        public string info;
    };
    private Dictionary<string,OneInfomation> InfoDictionary = new Dictionary<string,OneInfomation>();

    ......
       
 if (InfoDictionary.ContainsKey(titile))
{
    InfoDictionary[titile].isDirty = true;
    InfoDictionary[titile].info = "...";
}

上面这种情况是可以的，但是如果 OneInfomation 是一个结构的话，就会报错

报错信息
需要改成下面这个亚子

if (InfoDictionary.ContainsKey(titile))
{
    OneInfomation one_info = new OneInfomation();
    one_info.isDirty = true;
    one_info.info = "...";
    InfoDictionary[titile] = one_info;
}

参考：https://stackoverflow.com/questions/6255305/modify-struct-variable-in-a-dictionary