C# 0 The Complete Reference

Creating an Attribute

In an attribute class, you will define the members that support the attribute. Often attribute 

classes are quite simple, containing just a small number of fields or properties. For example, 

an attribute might define a remark that describes the item to which the attribute is being 

attached. Such an attribute might look like this:

 [AttributeUsage(AttributeTargets.All)]

public class RemarkAttribute : Attribute {

  string pri_remark; // underlies Remark property

  public RemarkAttribute(string comment) {

    pri_remark = comment;

  }

  public string Remark {

    get {

      return pri_remark;

    }

  }

}

Let’s look at this class, line by line.

The name of this attribute is 

RemarkAttribute

. Its declaration is preceded by the 

AttributeUsage

 attribute, which specifies that 

RemarkAttribute

 can be applied to all 

types of items. Using 

AttributeUsage

, it is possible to narrow the list of items to which 

an attribute can be attached, and we will examine its capabilities later in this chapter.

Next,

RemarkAttribute

 is declared and it inherits