.net中属性Attribute

    .  net中的属性attribute,有的地方也叫特性了，通常是用来修饰类，当然还可以修接口、方法、字段。

加了attribute属性的地方，可以通常过反射的方式来取得特性值。从而进行一些过滤操作。

   用户可以通过继承System.Attribute类来实现自定义的属性。在使用的地方使用反射机制来使用。

   以下是一些用例代码：

   using System;using System.Collections.Generic;using System.Text;namespace Tom.Test{ public enum Animal { // Pets. Dog = 1, Cat, Bird, } public class AnimalTypeAttribute : Attribute { public AnimalTypeAttribute(Animal pet) { thePet = pet; } // Keep a variable internally ... protected Animal thePet; // .. and show a copy to the outside world. public Animal Pet { get { return thePet; } set { thePet = value; } } } public class AnimalTypeTestClass { [AnimalType(Animal.Dog)] public void DogMethod() { } [AnimalType(Animal.Cat)] public void CatMethod() { Console.Write("#Cat#"); } [AnimalType(Animal.Bird)] public void BirdMethod() { } }}
下面是调用的示例：

     using System;using System.Collections.Generic;using System.Web;using System.Web.UI;using System.Web.UI.WebControls;using Tom.Test;using System.Reflection;public partial class t_TestAttr : System.Web.UI.Page{ protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { GetInfo(); } } protected void GetInfo() { AnimalTypeTestClass testClass = new AnimalTypeTestClass(); Type type = typeof(AnimalTypeTestClass);//testClass.GetType(); // Iterate through all the methods of the class. foreach (MethodInfo mInfo in type.GetMethods()) { // Iterate through all the Attributes for each method. foreach (Attribute attr in Attribute.GetCustomAttributes(mInfo)) { // Check for the AnimalType attribute. if (attr.GetType() == typeof(AnimalTypeAttribute)) { rdiv.InnerHtml += string.Format("<br/>Method {0} has a pet {1} attribute.", mInfo.Name, ((AnimalTypeAttribute)attr).Pet); rdiv.InnerHtml += string.Format("<br/>Type is {0}", typeof(AnimalTypeAttribute)); //mInfo.Invoke(testClass,new object[0]); 方法调用 } } } }}

    结果:

        Method DogMethod has a pet Dog attribute.
        Type is Tom.Test.AnimalTypeAttribute
       Method CatMethod has a pet Cat attribute.
       Type is Tom.Test.AnimalTypeAttribute
       Method BirdMethod has a pet Bird attribute.
       Type is Tom.Test.AnimalTypeAttribute