[Via Dan Fernandez]

Introduction to C# Generics

Some snippets from the article for introduction ...

Generics allow you to define type-safe data structures, without committing to actual data types. This results in a significant performance boost and higher quality code, because you get to reuse data processing algorithms without duplicating type-specific code.

Consider an everyday data structure such as a stack, providing the classic Push() and Pop() methods. When developing a general-purpose stack, you would like to use it to store instances of various types. Under C# 1.1, you have to use an Object-based stack, meaning that the internal data type used in the stack is an amorphous Object, and the stack methods interact with Objects:

 public class Stack {
     object[] m_Items;
     public void Push(object item)
     {...}
     public object Pop()
     {...}
} 

Generics allow you to define type-safe classes without compromising type safety, performance, or productivity. You implement the server only once as a generic server, while at the same time you can declare and use it with any type. To do that, use the and > brackets, enclosing a generic type parameter. For example, here is how you define and use a generic stack:

 public class Stack {
    T[] m_Items;
    public void Push(T item)    {...}
    public T Pop()    {...}
 }
 Stack stack = new Stack();
 stack.Push(1);
 stack.Push(2);
 int number = stack.Pop();