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.Net基础加强05

时间:2014-08-13 12:32:56      阅读:275      评论:0      收藏:0      [点我收藏+]

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垃圾回收(先了解以后再研究)

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

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            ////FileStream fs;
            ////fs.Dispose(
            //Person p1;

            #region 弱引用

            //引用的意思就是:当一个对象没有变量引用的时候,这时就可以被垃圾回收了。
            //但是接下来如果要是再想用该对象的话也是不可能的,因为即便还没有垃圾回收,但是这个对象已经无法在引用到了(虽然堆内存中,但是找不到该对象了。)
            //这时,当一个对象没有任何变量引用时,我们可以使用一个WeakReference(弱引用)来保持对这个对象的“引用”,这时虽然对该对象“弱引用”了,
            //但是这个对象仍然是可以被垃圾回收的,如果在下次使用这个对象的时候,该对象还没有被垃圾回收,则可以通过弱引用直接找到该对象,然后继续使用,如果已经被垃圾回收了,则需要重新创建这个对象。

            //Person p = new Person();
            //p.Age = 25;
            //p.Name = "叶长种";
            //p.Email = "826217795@qq.com";

            ////p.Email...
            ////Person tmp = p;
            ////p = null;

            ////GC.Collect();

            ////p = new Person();
            ////p.Name = "叶长种";
            ////p.Age = 25;
            ////p.Email = "826217795@qq.com";

            #endregion


            #region 通过代码来实现弱引用

            Person p = new Person();
            p.Name = "叶长种";
            p.Age = 25;
            p.Email = "826217795@qq.com";

            //弱引用
            WeakReference wkReference = new WeakReference(p);
            p = null;
            GC.Collect();

            //if (wkReference.Target != null)
            //{
            //    object o = wkReference.Target;
            //}

            //假设某个时间段的时候又要使用这个对象了。
            object o = wkReference.Target;

            if (o != null && wkReference.IsAlive)
            {
                Person p1 = o as Person;
                Console.WriteLine("{0}     {1}    {2}", p1.Name, p1.Age, p1.Email);
            }
            else
            {
                Console.WriteLine("重新创建对象吧,已经被垃圾回收了。");
            }

            Console.ReadKey();

            #endregion

        }
    }

    public class Person : IDisposable
    {
        public string Name
        {
            get;
            set;
        }
        public int Age
        {
            get;
            set;
        }
        public string Email
        {
            get;
            set;
        }

        public void Say()
        {

        }


        #region IDisposable 成员

        public void Dispose()
        {
            //编写代码,调用api,
        }
        #endregion

    }
}

集合

using System.Collections;(非泛型集合)

using System.Collections.Generic;(泛型集合)

“类似数组”集合:ArrayList,List<>

“键值对”集合(“哈希表”集合):Hashtable,Dictionary<K,V>

“堆栈”集合:Stack,Stack<T>(LIFO)

“队列”集合:Queue,Queue<T>(LIFO)

“可排序键值对”集合

Set集合

Dictionary集合

“双向链表”集合

 class Program
    {
        static void Main(string[] args)
        {
            #region ArrayList集合

            //ArrayList arrList = new ArrayList();
            //arrList.Add(10);
            //arrList.Add("10");
            //arrList.Add(new Person() { Name = "叶长种" });
            //arrList.Add(99.9);
            //arrList.Add(new int[] { 1, 2, 3, 4, 5 });
            //arrList.AddRange(new string[] { "叶长种", "詹姆斯", "科比" });

            ////arrList.RemoveAt(2);//删除索引为2的集合

            //for (int i = 0; i < arrList.Count; i++)
            //{
            //    arrList.RemoveAt(i);
            //}   //结果为 4 8

            ////arrList.Clear(); //清空集合

            //Console.WriteLine(arrList.Count);
            //Console.WriteLine(arrList.Capacity);
            //Console.ReadKey();



            //string str = "叶长种";
            //int n = 0;
            //try
            //{
            //    for (int i = 0; i < 30; i++)
            //    {
            //        n = i;
            //        str += str;
            //    }
            //}
            //catch
            //{
            //    Console.WriteLine(n);
            //    Console.WriteLine(str.Length);
            //}
            //Console.WriteLine(str);
            //Console.ReadKey();



            ////Array
            //int[] arr = new int[] { 1, 2, 3 };
            //Console.WriteLine(arr.GetType().ToString());
            //Console.WriteLine(arr.GetType().BaseType.ToString());
            //Console.WriteLine(arr.GetType().BaseType.BaseType.ToString());
            //Console.ReadKey();



            //ArrayList arrList = new ArrayList();

            #region MyRegion
            //arrList.Add(10);
            //arrList.Add("叶长种");
            //Person p1 = new Person();
            //p1.Name = "詹姆斯";

            //Person p2 = new Person();
            //p2.Name = "科比";


            //arrList.Add(p1);
            //arrList.Add(p2);

            //arrList.Remove(10);
            //arrList.Remove(p2);
            //Console.WriteLine(arrList.Count);
            //Console.WriteLine(arrList.Capacity);
            //Console.ReadKey();

            #endregion

            //Person p1 = new Person();
            //p1.Name = "yzk";
            //p1.Age = 18;
            //p1.Email = "yzk@itcast.cn";

            //Person p2 = new Person();
            //p2.Name = "yzk";
            //p2.Age = 18;
            //p2.Email = "yzk@itcast.cn";

            //string s1 = new string(new char[] { ‘a‘, ‘b‘, ‘c‘ });

            //arrList.Add(p1);
            //arrList.Add(p2);
            //arrList.Add(s1);

            //arrList.Remove(p2);
            //arrList.Remove("abc");//这样也会把s1删掉

            ////arrList.ToArray() //把集合变成数组

            //Console.WriteLine(arrList.Count);
            //Console.ReadKey();

            #endregion

            #region 集合中的Sort方法

            //ArrayList arrList = new ArrayList();
            #region 
            ////arrList.Add(9);
            ////arrList.Add(19);
            ////arrList.Add(3);
            ////arrList.Add(7);
            ////arrList.Add(5);
            ////arrList.Sort();

            //arrList.Add("sk");
            //arrList.Add("jk");
            //arrList.Add("yzk");
            //arrList.Add("nll");
            //arrList.Add("yhb");
            //arrList.Add("ml");
            //arrList.Sort();//升序排序

            //for (int i = 0; i < arrList.Count; i++)
            //{
            //    Console.WriteLine(arrList[i]);
            //}
            //Console.ReadKey();

          
            #endregion

            ArrayList arrList = new ArrayList();

            Person sk = new Person() { Name = "sk", Age = 18, Email = "sk@itcast.cn" };
            Person jk = new Person() { Name = "jk", Age = 17, Email = "jk@itcast.cn" };
            Person yzk = new Person() { Name = "yzk", Age = 16, Email = "yzk@itcast.cn" };
            Person yhb = new Person() { Name = "yhb", Age = 15, Email = "yhb@itcast.cn" };
            arrList.Add(sk);
            arrList.Add(jk);
            arrList.Add(yzk);
            arrList.Add(yhb);

            //Sort()内部只支持升序,除非自己写CompareTo方法
            arrList.Sort();

            //[a,b,c,d]
            //a.CompareTo(b)

            //或者另外一个解决方案是,先升序排序再调用Reverse()反转数组。来实现降序的功能。
            //arrList.Reverse();


            for (int i = 0; i < arrList.Count; i++)
            {
                Person p = arrList[i] as Person;
                Console.WriteLine(p.Name);
            }

            Console.ReadKey();
            #endregion
        }
    }

    public class Person : IComparable
    {
        public string Name
        {
            get;
            set;
        }
        public int Age
        {
            get;
            set;
        }
        public string Email
        {
            get;
            set;
        }


        #region IComparable 成员

        public int CompareTo(object obj)
        {
            Person p = obj as Person;
            return this.Age - p.Age;
        }

        #endregion
    }

集合排序ICompare接口使用

 

  class Program
    {
        static void Main(string[] args)
        {
            ArrayList arrList = new ArrayList();
            Person sk = new Person() { Name = "skk", Age = 18, Email = "sk@itcast.cn" };
            Person jk = new Person() { Name = "jk", Age = 17, Email = "jk@itcast.cn" };
            Person yzk = new Person() { Name = "yzkk", Age = 16, Email = "yzk@itcast.cn" };
            Person yhb = new Person() { Name = "yhbbbbbb", Age = 15, Email = "yhb@itcast.cn" };
            arrList.Add(sk);
            arrList.Add(jk);
            arrList.Add(yzk);
            arrList.Add(yhb);
            //arrList.Sort(new SortByAgeAsc());
            arrList.Sort(new SortByNameAsc());

            for (int i = 0; i < arrList.Count; i++)
            {
                Console.WriteLine(((Person)arrList[i]).Name);
            }
            Console.ReadKey();

            //1.按照年龄降序排序

            //2.按照姓名升序排序


        }
    }


    public class SortByAgeAsc : IComparer
    {

        #region IComparer 成员

        public int Compare(object x, object y)
        {
            Person px = x as Person;
            Person py = y as Person;
            return px.Age - py.Age;

        }

        #endregion
    }

    public class SortByNameAsc : IComparer
    {

        #region IComparer 成员

        public int Compare(object x, object y)
        {
            Person px = x as Person;
            Person py = y as Person;
            return px.Name.Length - py.Name.Length;
        }

        #endregion
    }

    public class Person
    {
        public string Name
        {
            get;
            set;
        }
        public int Age
        {
            get;
            set;
        }
        public string Email
        {
            get;
            set;
        }
    }

 

.Net基础加强05,布布扣,bubuko.com

.Net基础加强05

标签:style   blog   color   使用   os   io   for   ar   

原文地址:http://www.cnblogs.com/yechangzhong-826217795/p/3909474.html

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