Understanding C# Generics with Examples

Generics in C# provide flexibility and type safety for classes, methods, interfaces, and more. This blog explores different types of generics in C# with examples.

1. Generic Classes

public class GenericClass
{
    private T data;

    public void SetValue(T value) => data = value;

    public T GetValue() => data;
}

// Usage
var intInstance = new GenericClass();
intInstance.SetValue(10);
Console.WriteLine(intInstance.GetValue()); // Output: 10

var stringInstance = new GenericClass();
stringInstance.SetValue("Hello");
Console.WriteLine(stringInstance.GetValue()); // Output: Hello

2. Generic Methods

public class GenericMethods
{
    public void Print(T value)
    {
        Console.WriteLine(value);
    }
}

// Usage
var obj = new GenericMethods();
obj.Print(123);          // Output: 123
obj.Print("Generics");   // Output: Generics

3. Generic Interfaces

public interface IGenericInterface
{
    T Process(T input);
}

public class GenericImplementation : IGenericInterface
{
    public int Process(int input) => input * 2;
}

// Usage
var instance = new GenericImplementation();
Console.WriteLine(instance.Process(5)); // Output: 10

4. Generic Delegates

public delegate T GenericDelegate(T input);

class Program
{
    public static int Double(int x) => x * 2;

    public static string Uppercase(string x) => x.ToUpper();

    static void Main()
    {
        GenericDelegate intDelegate = Double;
        Console.WriteLine(intDelegate(5)); // Output: 10

        GenericDelegate stringDelegate = Uppercase;
        Console.WriteLine(stringDelegate("hello")); // Output: HELLO
    }
}

5. Generic Constraints

public class GenericWithConstraints where T : class
{
    public T Value { get; set; }
}

// Usage
var instance = new GenericWithConstraints { Value = "Hello" };
Console.WriteLine(instance.Value); // Output: Hello

6. Generic Structs

public struct GenericStruct
{
    public T Value { get; set; }
}

// Usage
var genericStruct = new GenericStruct { Value = 42 };
Console.WriteLine(genericStruct.Value); // Output: 42

7. Generic Enums (with Constraints)

public class GenericEnum where T : Enum
{
    public T EnumValue { get; set; }
}

// Usage
var enumInstance = new GenericEnum { EnumValue = DayOfWeek.Monday };
Console.WriteLine(enumInstance.EnumValue); // Output: Monday

8. Generic Events

public class GenericEvent
{
    public event Action OnValueChanged;

    public void Trigger(T value)
    {
        OnValueChanged?.Invoke(value);
    }
}

// Usage
var eventInstance = new GenericEvent();
eventInstance.OnValueChanged += value => Console.WriteLine($"Value changed to: {value}");
eventInstance.Trigger("New Value"); // Output: Value changed to: New Value

9. Generic Collections

C# offers several built-in generic collections:

• List
• Dictionary
• Queue
• Stack

Conclusion

Generics in C# are a powerful tool that provides flexibility, type safety, and performance. Use these examples to explore and master the world of generics in your applications.