Skip to content
.Net Book

Generic Class Syntax

Context: The syntax for generic classes uses one or more type parameters between angle brackets <> after the class name. Type parameters are placeholders for actual types provided at instantiation. Constraints (see section 11.4) can be applied to restrict allowed types.

Usage Example

Section titled “Usage Example”
using System;


// Generic class with two type parameters
public class Pair<T1, T2>
{
    public T1 First { get; set; }
    public T2 Second { get; set; }


    public void Display()
    {
        Console.WriteLine($"({First}, {Second})");
    }
}


class Program
{
    static void Main()
    {
        Pair<int, string> pair1 = new Pair<int, string>();
        pair1.First = 10;
        pair1.Second = "Ten";
        pair1.Display();


        var pair2 = new Pair<double, bool> { First = 3.14, Second = true };
        pair2.Display();
    }
}

Output console

Section titled “Output console”
Terminal window
dotnet run
(10, Ten)
(3.14, True)

Important notes

Section titled “Important notes”
  • The generic class name can be used with different types.
  • Type inference is not available for instantiation (types must be specified).
  • Type parameters can be used as field, property, method parameter, and return types.

Real-world usage example

Section titled “Real-world usage example”

KeyValuePair<TKey, TValue> – Used in Dictionary<TKey, TValue> to represent a key/value pair.
See .NET docs on generics.

Section titled “Related sections”