C# 3.0 Cookbook, 3rd Edition

4.2. Understanding Generic Types

Problem

You need to understand how the .NET types work for generics and how Generic .NET types differ from regular .NET types.

Solution

A couple of quick experiments can show the differences between regular .NET types and generic .NET types. When a regular .NET type is defined, it looks like the FixedSizeCollection type defined in Example 4-1.

Example 4-1. FixedSizeCollection: a regular .NET type

public class FixedSizeCollection { /// <summary> /// Constructor that increments static counter /// and sets the maximum number of items /// and sets the maximum number of items /// and sets the maximum number of items /// </summary> /// <param name="maxItems"></param> public FixedSizeCollection(int maxItems) { FixedSizeCollection.InstanceCount++; this.Items = new object[maxItems]; } /// <summary> /// Add an item to the class whose type /// is unknown as only object can hold any type /// </summary> /// <param name="item">item to add</param> /// <returns>the index of the item added</returns> public int AddItem(object item) { if (this.ItemCount < this.Items.Length) { this.Items[this.ItemCount] = item; return this.ItemCount++; } else throw new Exception("Item queue is full"); } /// <summary> /// Get an item from the class /// </summary> /// <param name="index">the index of the item to get</param> /// <returns>an item of type object</returns> public object GetItem(int index) { if (index >= this.Items.Length && index >= 0) throw new ArgumentOutOfRangeException("index"); ...