rspec/rules/S4052/csharp/rule.adoc

== Why is this an issue?

With the advent of .NET framework version 2, certain practices have become obsolete.

In particular, exceptions should now extend ``++System.Exception++`` instead of ``++System.ApplicationException++``. Similarly, generic collections should be used instead of the older, non-generic, ones. Finally when creating an XML view, you should not extend ``++System.Xml.XmlDocument++``.

This rule raises an issue when an externally visible type extends one of these types:

* ``++System.ApplicationException++``
* ``++System.Xml.XmlDocument++``
* ``++System.Collections.CollectionBase++``
* ``++System.Collections.DictionaryBase++``
* ``++System.Collections.Queue++``
* ``++System.Collections.ReadOnlyCollectionBase++``
* ``++System.Collections.SortedList++``
* ``++System.Collections.Stack++``


=== Noncompliant code example

[source,csharp]
----
using System;
using System.Collections;

namespace MyLibrary
{
  public class MyCollection : CollectionBase  // Noncompliant
  {
  }
}
----


=== Compliant solution

[source,csharp]
----
using System;
using System.Collections;

namespace MyLibrary
{
  public class MyCollection : Collection<T>
  {
  }
}
----


ifdef::env-github,rspecator-view[]

'''
== Implementation Specification
(visible only on this page)

=== Message

Refactor this type not to derive from an outdated type '{0}'.


endif::env-github,rspecator-view[]