Csharp/C Sharp by API/System/Attribute

Attribute.GetCustomAttribute

<source lang="csharp"> using System; using System.Reflection;

[AttributeUsage(AttributeTargets.All)] class RemarkAttribute : Attribute {

 string remarkValue; // underlies remark property 

 public string supplement; // this is a named parameter 

 public RemarkAttribute(string comment) { 
   remarkValue = comment; 
   supplement = "None"; 
 } 

 public string remark { 
   get { 
     return remarkValue; 
   } 
 } 

}

[RemarkAttribute("This class uses an attribute.",

                supplement = "This is additional info.")] 

class UseAttrib {

 // ... 

}

public class NamedParamDemo {

 public static void Main() {  
   Type t = typeof(UseAttrib); 

   Console.Write("Attributes in " + t.Name + ": "); 

   object[] attribs = t.GetCustomAttributes(false);  
   foreach(object o in attribs) { 
     Console.WriteLine(o); 
   } 

   // Retrieve the RemarkAttribute. 
   Type tRemAtt = typeof(RemarkAttribute); 
   RemarkAttribute ra = (RemarkAttribute) 
         Attribute.GetCustomAttribute(t, tRemAtt); 

   Console.Write("Remark: "); 
   Console.WriteLine(ra.remark); 

   Console.Write("Supplement: "); 
   Console.WriteLine(ra.supplement); 
 }  

}

 </source>

Attribute.GetCustomAttribute(Type t, Type tR);

<source lang="csharp"> using System; using System.Reflection;

[AttributeUsage(AttributeTargets.All)] public class MyAttribute : Attribute {

 public string remark;

 public string supplement; 

 public MyAttribute(string comment) { 
   remark = comment; 
   supplement = "None"; 
 } 

 public string Remark { 
   get { 
     return remark; 
   } 
 } 

}

[MyAttribute("This class uses an attribute.",

                supplement = "This is additional info.")] 

class UseAttrib { }

class MainClass {

 public static void Main() {  
   Type t = typeof(UseAttrib); 

   Console.Write("Attributes in " + t.Name + ": "); 

   object[] attribs = t.GetCustomAttributes(false);  
   foreach(object o in attribs) { 
     Console.WriteLine(o); 
   } 

   // Retrieve the MyAttribute. 
   Type tRemAtt = typeof(MyAttribute); 
   MyAttribute ra = (MyAttribute) 
         Attribute.GetCustomAttribute(t, tRemAtt); 

   Console.Write("Remark: "); 
   Console.WriteLine(ra.remark); 

   Console.Write("Supplement: "); 
   Console.WriteLine(ra.supplement); 
 }  

}

 </source>

Attribute.Remove()

<source lang="csharp"> using System; using System.Linq; using System.Collections; using System.Collections.Generic; using System.Xml; using System.Xml.Linq; public class MainClass {

   public static void Main() {
       XElement firstParticipant;
       XDocument xDocument = new XDocument(
         new XElement("Books", firstParticipant =
           new XElement("Book",
             new XAttribute("type", "Author"),
             new XElement("FirstName", "J"),
             new XElement("LastName", "R"))));
       Console.WriteLine(xDocument);
       firstParticipant.Attribute("type").Remove();
       Console.WriteLine(xDocument);
   }

}

 </source>

Attribute.Value

<source lang="csharp"> using System; using System.Linq; using System.Collections; using System.Collections.Generic; using System.Xml; using System.Xml.Linq; public class MainClass {

   public static void Main() {
       XElement firstParticipant;
       XDocument xDocument  = new XDocument(
         new XElement("Books", firstParticipant =
           new XElement("Book",
             new XAttribute("type", "Author"),
             new XAttribute("experience", "first-time"),
             new XElement("FirstName", "J"),
             new XElement("LastName", "R"))));
       Console.WriteLine(xDocument);
       firstParticipant.Attribute("experience").Value = "beginner";
       Console.WriteLine(xDocument);
   }

}

 </source>

extends Attribute

<source lang="csharp"> using System;

public class MainClass {

   public static void Main() 
   {
       UnitTest u;
       Console.Write("Class1 UnitTest attribute: ");
       u = (UnitTest) Attribute.GetCustomAttribute(typeof(Class1), typeof(UnitTest));
       Console.WriteLine(u.Written());
       Console.Write("Class2 UnitTest attribute: ");
       u = (UnitTest) Attribute.GetCustomAttribute(typeof(Class2), typeof(UnitTest));
       Console.WriteLine(u.Written());
   }

}

public class UnitTest : Attribute {

   bool bWritten;
   public bool Written()
   {
       return bWritten;
   }
   public UnitTest(bool Written)
   {
       bWritten = Written;
   }

} // apply the UnitTest attribute to two classes [UnitTest(true)] public class Class1 { } [UnitTest(false)] public class Class2 { }

 </source>