C# 预定义和自定义属性

 C# 属性的使用包括预定义和自定义，类似异常，说白了就是类，成员，方法，前面的[]的使用，直接上代码：

using System; using System.Collections.Generic; using System.Text; using System.Diagnostics; using System.Reflection; namespace CustomerAttribute { class Program { static void Main(string[] args) { ClsCustomerAttribute Attribute; Type type = typeof(ClsB); //查询类属性 foreach (Attribute attr in type.GetCustomAttributes(true)) { Attribute = attr as ClsCustomerAttribute; if (null != Attribute) { Console.WriteLine(" CLASS {0} Attribute IS :/n{1}/n",type.Name, Attribute.Description); } } //查询类方法属性 foreach (MethodInfo method in type.GetMethods()) { foreach (Attribute attr in method.GetCustomAttributes(true)) { Attribute = attr as ClsCustomerAttribute; if (null != Attribute) { Console.WriteLine("Method {0} Attribute IS:/n{1}/n", method.Name, Attribute.Description); } } } //查询类成员属性 foreach (MemberInfo member in type.GetMembers()) { foreach (Attribute attr in member.GetCustomAttributes(true)) { Attribute = attr as ClsCustomerAttribute; if (null != Attribute) { Console.WriteLine("Member {0} Attribute IS:/n{1}", member.Name, Attribute.Description); } } } Console.Read(); } } public class ClsA { // ”Obsolete”attribute，它标记了一个不该再被使用的语言元素（译者注：这里的元素是方法） //这里的Obsolete 是预定义预定义 Attributes //该属性的第一个参数是string类型，它解释为什么该元素被荒弃，以及解决方案 //第二个参数如果是True则告诉编译器视为一种错误，如果为False编译器会产生一个警告。 //编译的时候，会报错：错误 1 “TingTing.AnyClass.Old()”已过时:“Don’t use Old method, use New method” [Obsolete("Don’t use Old method, use New method", false)] public static void Old() { Console.WriteLine("Old Method"); } public static void New() { Console.WriteLine("New Method"); } } [ClsCustomerAttribute("this is a class Description")] public class ClsB { [ClsCustomerAttribute("This is a Integer member Description.")] public int intA; [ClsCustomerAttribute("This is a String member Description.")] public string stringA; //由于我们自定义的属性ClsCustomerAttribute，只允许放在CLASS上， //编译报错,错误 2 属性“ClsCustomerAttribute”在该声明类型中无效。它只在“class”声明中有效。 [ClsCustomerAttribute("this is a method Description")] public void MethodA() { Console.WriteLine("fkshf"); } } /// <summary> /// 自定义属性类 /// AttributeUsage 类是另一预定义类,它用来控制我们自定义attribute的3个属性， /// 1:AttributeTargets.All 自定义attribute可以放置在哪些类型上，例如ALL表示全部，而CLASS表示类 /// 2:自定义attribte能在同一语言元素上使用多次 /// 3:是否可被继承Inherited = true/false /// </summary> [AttributeUsage(AttributeTargets.All, AllowMultiple = true, Inherited = true)] public class ClsCustomerAttribute : Attribute { protected String description; public ClsCustomerAttribute(string Descrition_in) { this.description = Descrition_in; } public String Description { get { return this.description; } } } }   

 

PS:工程里需要引用System.Configuration.dll

详细请参考下面的BLOG：

http://www.cnblogs.com/raylynn/archive/2007/06/29/800255.html