Hashtable 数据遍历的几种方式

Hashtable 在集合中称为键值对，它的每一个元素的类型是 DictionaryEntry,由于Hashtable对象的键和值都是Object类型，决定了它可以放任何类型的数据，

下面我就把Hashtable对象中放置定义的一个类的几个对象。

创建的类如下：

 

 class Person
    {
        private int age;
        public int Age
        {
            get { return age; }
            set { age = value; }
        }
        private string name;
        public string Name
        {
            get { return name; }
            set { name = value; }
        }
        private string email;
        public string Email
        {
            get { return email; }
            set { email = value; }
        }
    }

 

Hashtable的几种遍历方法如下：

 

 static void Main(string[] args)
        {
            Person person1 = new Person();
            person1.Age = 34;
            person1.Name = "Jacky";
            person1.Email = "Jacky@gmail.com";

            Person person2 = new Person();
            person2.Age = 23;
            person2.Name = "Ajay";
            person2.Email = "Ajay@gmail.com";

            Person person3 = new Person();
            person3.Age = 12;
            person3.Name = "Bill";
            person3.Email = "Bill@gmail.com";

            Person person4 = new Person();
            person4.Age = 23;
            person4.Name = "Gace";
            person4.Email = "Gace@gmail.com";

            Person person5 = new Person();
            person5.Age = 45;
            person5.Name = "Jim";
            person5.Email = "Jim@gmail.com";

            Hashtable ht = new Hashtable();
            ht.Add("1", person1);
            ht.Add("2", person2);
            ht.Add("3", person3);
            ht.Add("4", person4);
            ht.Add("5", person5);
            Console.WriteLine("请输入你的查询的用户名:");
            string strName = Console.ReadLine();
            //第一种方法
             foreach (string item in ht.Keys)
            {
                Person p = (Person)ht[item];
                if (strName == p.Name)
                {
                    Console.WriteLine("查询后的结果是:" + p.Name + "\t" + p.Email + "\t" + p.Age);
                }
            }



            //第二种方法
             foreach (Person item in ht.Values)
            {
                if (item.Name == strName)
                {
                    Console.WriteLine("查询后的结果是:" + item.Name + "\t" + item.Email + "\t" + item.Age);
                }

            }
            //第三种方法
             foreach (DictionaryEntry item in ht)
            {
                if (strName == ((Person)item.Value).Name)
                {
                    Console.WriteLine("查询后的结果是:" + ((Person)item.Value).Name + "\t" + ((Person)item.Value).Email + "\t" + ((Person)item.Value).Age);
                }
            }

            //第四种方法
             IDictionaryEnumerator id = ht.GetEnumerator();
            while (id.MoveNext())
            {
             Person p =   (Person)ht[id.Key];
             if (p.Name == strName)
             {
                 Console.WriteLine("查询后的结果是:" + p.Name + "\t" + p.Email + "\t" + p.Age);
             }
            }

        }