从ScottGu's Blogs上看到了关于Vs2008中.NET Framework3.5语言(Jeffry Zhao说这是 C#3.0的特性,自己见识太短了)的新特性,其中有一个叫做Extension Methods(http://weblogs.asp.net/scottgu/archive/2007/03/13/new-orcas-language-feature-extension-methods.aspx)
这功能让我激动不已。它可以为某一类型的变量(如string,int等)添加上我们自己增加的一些“额外”的方法,比如我们自己为一string 类型的的变量strEmail添加上一个IsValidEmailAddress方法,怎么样?这个方法是否心动?原来我们要实现这个功能着实是会费一番功夫,可是如今有了Extension Methods,很简单即可搞定它:
方法如下:
新添加一个静态类,比如代码为:
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using System;
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using System.Data;
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using System.Configuration;
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using System.Linq;
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using System.Web;
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using System.Web.Security;
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using System.Web.UI;
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using System.Web.UI.WebControls;
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using System.Web.UI.WebControls.WebParts;
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using System.Web.UI.HtmlControls;
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using System.Xml.Linq;
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using System.Text.RegularExpressions;
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/// <summary>
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/// Summary description for MyStaticExtension
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/// </summary>
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public static class MyStaticExtension
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{
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public static bool IsValidEmailAddress(this string strEmail)
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{
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Regex regex = new Regex(@"^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$");
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return regex.Match(strEmail).Success;
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}
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public static bool IsBiggerThan10(this int intNumber)
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{
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if (intNumber > 10) return true;
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return false;
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}
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}
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在这个类中有两个静态的方法,其中一个是IsValidEmailAddress(this string strEmail),另外一个是IsBiggerThan10(this int intNumber);![](/Images/OutliningIndicators/None.gif)
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![](/Images/OutliningIndicators/None.gif)
注意这两个方法均是静态的,而且你注意到了么,它的参数前都有一个this关键字来修饰,这就是告诉编辑器,要将string类型的变量加上该IsValidEmailAddress方法,将int类型的变量加上IsBiggerThan10的方法。OK,既然准备好了,我们就开始使用它:
首先,因为我们在该工程中只用到了一个命名空间,所以你在使用它的类中可以using MyStaticExention,也可以不using,二者均可
然后我们就可以直接在类中使用了:
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string strEmail = "aa";
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strEmail.IsValidEmailAddress();
![](/Images/OutliningIndicators/None.gif)
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![](/Images/OutliningIndicators/None.gif)
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int a = 10;
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bool bl = a.IsBiggerThan10();
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这个功能真让人振奋!
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