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步步为营VS 2008 + .NET 3.5(3) - C# 3.0新特性之Automatic Properties(自动属性)、Object Initializers(对象初始化器)、Collection Initializers(集合初始化器)和Extension Methods(扩展方法)


作者:webabcd


介绍
    ·Automatic Properties(自动属性)
    ·Object Initializers(对象初始化器)
    ·Collection Initializers(集合初始化器)
    ·Extension Methods(扩展方法)


示例
AutomaticProperties.cs(自动属性)
using System;
using System.Data;
using System.Configuration;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Xml.Linq;

/// <summary>
/// AutomaticProperties(自动属性)的摘要说明
/// </summary>
public class AutomaticProperties
{
        public int ID { get; set; }

        // 上面的ID属性(自动属性)等同于下面的ID属性

        // private int _id;
        // public int ID
        // {
        //         get { return _id; }
        //         set { _id = value; }
        // }
}
 
ObjectInitializers.cs对象初始化器
using System;
using System.Data;
using System.Configuration;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Xml.Linq;

/// <summary>
/// ObjectInitializers(对象初始化器)的摘要说明
/// </summary>
public class ObjectInitializers
{
        public int ID { get; set; }
        public string Name { get; set; }

        public void ObjectInitializersTest()
        {
                ObjectInitializers oi = new ObjectInitializers { ID = 1, Name = "webabcd" };

                // 上面的oi对象(对象初始化器)等同于下面的oi对象

                // ObjectInitializers oi = new ObjectInitializers();
                // oi.ID = 1;
                // oi.Name = "webabcd";
        }
}
 
CollectionInitializers.cs集合初始化器
using System;
using System.Data;
using System.Configuration;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Xml.Linq;

using System.Collections.Generic;

/// <summary>
/// CollectionInitializers(集合初始化器)的摘要说明
/// </summary>
public class CollectionInitializers
{
        public int ID { get; set; }
        public string Name { get; set; }

        public void CollectionInitializersTest()
        {
                List<CollectionInitializers> list = new List<CollectionInitializers>
                {
                        new CollectionInitializers { ID = 1, Name = "webabcd" },
                        new CollectionInitializers { ID = 2, Name = "webabcdefg" },
                        new CollectionInitializers { ID = 3, Name = "webabcdefghijklmn" }
                };

                // 上面的list集合(集合初始化器)等同于下面的list集合

                // List<CollectionInitializers> list = new List<CollectionInitializers>();
                // list.Add(new CollectionInitializers { ID = 1, Name = "webabcd" });
                // list.Add(new CollectionInitializers { ID = 2, Name = "webabcdefg" });
                // list.Add(new CollectionInitializers { ID = 3, Name = "webabcdefghijklmn" });
        }
}
 
ExtensionMethods.cs扩展方法
using System;
using System.Data;
using System.Configuration;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Xml.Linq;

/// <summary>
/// ExtensionMethods 的摘要说明
/// </summary>
public class ExtensionMethods
{
        public void ExtensionMethodsTest()
        {
                string s = "123";
                // 使用string的ToInt32()扩展方法
                int i = s.ToInt32();
                // i == 123

                string[] ary = new string[] { "a", "b", "c" };
                // 使用object的In()扩展方法
                bool b = "b".In(ary);
                // b == true
        }
}

/// <summary>
/// 扩展方法(类和方法均为static
/// 使用的时候要引用该类的命名空间
/// </summary>
public static class MyExtensionMethods
{
        // this代表扩展方法应用于string类型上
        // ToInt32()是将string类型转换为int类型的扩展方法
        public static int ToInt32(this string s)
        {
                int i;
                Int32.TryParse(s, out i);

                return i;
        }

        // this代表扩展方法应用于object类型上
        // 该扩展方法需要一个类型为System.Collections.IEnumerable的参数
        // In()是判断一个object是否存在于一个System.Collections.IEnumerable中的扩展方法
        public static bool In(this object o, System.Collections.IEnumerable e)
        {
                foreach (object i in e)
                {
                        if (i.Equals(o))
                        {
                                return true;
                        }
                }

                return false;
        }
}
 
 

本文出自 “webabcd” 博客,请务必保留此出处http://webabcd.blog.51cto.com/1787395/344909

posted on 2011-08-03 19:58  .net 流氓  阅读(586)  评论(0编辑  收藏  举报