C# 4 and .NET 4

110 ❘ ChaPTer 5 Generics
Value types are contained within the memory of the generic instantiated class, and because every value type
can have different memory requirements, a new class for every value type is instantiated.
naming guidelines
If generics are used in the program, it helps when generic types can be distinguished from non-generic types.
Here are naming guidelines for generic types:
➤ Generic type names should be prefixed with the letter T.
➤
If the generic type can be replaced by any class because there’s no special requirement, and only one
generic type is used, the character T is good as a generic type name:
public class List { }
➤
public class LinkedList { }
If there’s a special requirement for a generic type (for example, it must implement an interface or
derive from a base class), or if two or more generic types are used, descriptive names should be used
for the type names:
public delegate void EventHandler(object sender, TEventArgs e);
public delegate TOutput Converter(TInput from);
public class SortedList { }
CreaTing generiC Classes
First start with a normal, non-generic simplified linked list class that can contain objects of any kind, and
later convert this class to a generic class.
With a linked list, one element references the next one. So, you must create a class that wraps the
object inside the linked list and references the next object. The class LinkedListNode contains a
property named Value that is initialized with the constructor. In addition to that, the LinkedListNode
class contains references to the next and previous elements in the list that can be accessed from
properties.
public class LinkedListNode
{
public LinkedListNode(object value)
{
this.Value = value;
}
public object Value { get; private set; }
}
public LinkedListNode Next { get; internal set; }
public LinkedListNode Prev { get; internal set; }
code snippet LinkedListObjects/LinkedListNode.cs
The LinkedList class includes First and Last properties of type LinkedListNode that mark the
beginning and end of the list. The method AddLast() adds a new element to the end of the list. First,
an object of type LinkedListNode is created. If the list is empty, the First and Last properties are
set to the new element; otherwise, the new element is added as the last element to the list. By
implementing the GetEnumerator() method, it is possible to iterate through the list with the
foreach statement. The GetEnumerator() method makes use of the yield statement for creating an
enumerator type.
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