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）

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 = "zhaosoft" };




// 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 = "zhaosoft";


}


}



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 = "zhaosoft" },




new CollectionInitializers

{ ID = 2, Name = "zhaosoft" },




new CollectionInitializers

{ ID = 3, Name = "zhaosoft" }


};




// 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 = "zhaosoft" });


// list.Add(new CollectionInitializers { ID = 2, Name = "zhaosoft" });


// list.Add(new CollectionInitializers { ID = 3, Name = "zhaosoft" });


}


}



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;


}


}