[Example: The example
using System;
[AttributeUsage(AttributeTargets.Class)]
public class HelpAttribute: Attribute
{
public HelpAttribute(string url) { // url is a positional parameter
...
}
public string Topic { // Topic is a named parameter
get {...}
set {...}
}
public string Url { get {...} }
}
defines an attribute class named HelpAttribute that has one positional parameter (string url) and one named parameter (string Topic). Although it is non-static and public, the property Url does not define a named parameter, since it is not read-write.