C#哈希表(HashTable)和Dictionary比较

添加数据时Hashtable快。频繁调用数据时Dictionary快。

Dictionary<K,V>是泛型的，当K或V是值类型时，其速度远远超过Hashtable。

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

namespace WindowsFormsApp1
{
    public class Student
    {
        private string _name;
        private int _age;

        public string Name { get => _name; set => _name = value; }
        public int Age { get => _age; set => _age = value; }
        
    }
}

private void button1_Click(object sender, EventArgs e)
        {
            Stopwatch sw = new Stopwatch();

            Hashtable hashtable = new Hashtable();

            Dictionary<int, Student> dict = new Dictionary<int, Student>();

            int countNum = 1000000;            
            sw.Start();
            for (int i = 0; i < countNum; i++)
            {
                Student s = new Student();
                s.Name = "n" + i.ToString();
                s.Age = i;
                hashtable.Add(i, s);
            }
            sw.Stop();
            Console.WriteLine(sw.ElapsedMilliseconds);  //输出: 817


            sw.Restart();
            for (int i = 0; i < countNum; i++)
            {
                Student s = new Student();
                s.Name = "n" + i.ToString();
                s.Age = i;
                dict.Add(i, s);
            }
            sw.Stop();
            Console.WriteLine(sw.ElapsedMilliseconds);  //输出: 859



            sw.Restart();
            for (int i = 0; i < countNum; i++)
            {
                hashtable.ContainsKey(i);
                Student s1 =(Student)hashtable[i];
                string str1 = s1.Name;
            }
            sw.Stop();
            Console.WriteLine(sw.ElapsedMilliseconds);  //输出: 137

            sw.Restart();
            for (int i = 0; i < countNum; i++)
            {
                dict.ContainsKey(i);
                string str=dict[i].Name;
            }
            sw.Stop();
            Console.WriteLine(sw.ElapsedMilliseconds);  //输出: 51

        }