C# 预定义和自定义属性

超、凢脫俗 2022-09-28 11:55 184阅读 0赞

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][http_www.cnblogs.com_raylynn_archive_2007_06_29_800255.html]

[http_www.cnblogs.com_raylynn_archive_2007_06_29_800255.html]: http://www.cnblogs.com/raylynn/archive/2007/06/29/800255.html