Generic Classes

Context: Generic classes allow you to define a class template with type parameters. This avoids duplicating code for different data types. The actual type is specified at instantiation. Generic classes provide compile-time type safety and improve performance by avoiding boxing/unboxing for value types.

Usage Example

using System;

public class Box<T>
{
    private T _content;

    public void Add(T content)
    {
        _content = content;
    }

    public T Get()
    {
        return _content;
    }
}

class Program
{
    static void Main()
    {
        Box<int> intBox = new Box<int>();
        intBox.Add(42);
        int value = intBox.Get();
        Console.WriteLine(value);

        Box<string> stringBox = new Box<string>();
        stringBox.Add("Hello");
        Console.WriteLine(stringBox.Get());
    }
}

Output console

dotnet run
42
Hello

Important notes

• Type parameters are placed between angle brackets <> after the class name.
• Value types are not boxed when used with generics.
• A generic class can have multiple type parameters.

Real-world usage example

.NET Collections – List<T>, Dictionary<TKey, TValue> and Queue<T> are generic classes used daily to store typed data.
See .NET docs on generic classes.

Related sections

• 11.1.1 Syntax
• 11.1.2 Type parameters naming T, TKey, TValue
• 11.2 Generic methods