[System.AttributeUsage(System.AttributeTargets.Class | System.AttributeTargets.Struct, AllowMultiple = true) // multiuse attribute ] public class Author : System.Attribute { string name; public double version; public Author(string name) { this.name = name; version = 1.0; // Default value } public string GetName() { return name; } } [Author("H. Ackerman")] private class FirstClass { // ... } // No Author attribute private class SecondClass { // ... } [Author("H. Ackerman"), Author("M. Knott", version = 2.0)] private class ThirdClass { // ... } class TestAuthorAttribute { static void Main() { PrintAuthorInfo(typeof(FirstClass)); PrintAuthorInfo(typeof(SecondClass)); PrintAuthorInfo(typeof(ThirdClass)); } private static void PrintAuthorInfo(System.Type t) { System.Console.WriteLine("Author information for {0}", t); System.Attribute[] attrs = System.Attribute.GetCustomAttributes(t); // reflection foreach (System.Attribute attr in attrs) { if (attr is Author) { Author a = (Author)attr; System.Console.WriteLine(" {0}, version {1:f}", a.GetName(), a.version); } } } }
输出结果:
Author information for FirstClass
H. Ackerman, version 1.00
Author information for SecondClass
Author information for ThirdClass
H. Ackerman, version 1.00