Interfaces

Context: An interface defines a contract that implementing classes must follow. It contains only signatures (methods, properties, events, indexers) without implementation.

Key Characteristics

• No fields or constructors.
• Members are implicitly public and abstract (before C# 8).
• A class can implement multiple interfaces.

public interface IDrawable
{
    void Draw();
}
public class Circle : IDrawable
{
    public void Draw() => Console.WriteLine("Drawing Circle");
}

Related Topics

• 4.5.1 Interface definition
• 4.5.2 Implementing an interface
• 4.5.3 Explicit interface implementation
• 4.5.4 Default interface methods C# 8 and later