Explicit interface implementation in C Sharp (C#) - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is explicit interface implementation in C#?

It is a way to implement interface members so they are only accessible through the interface, not through the class instance directly.

intermediate

Why use explicit interface implementation?

To avoid name conflicts when multiple interfaces have members with the same name, or to hide interface methods from the class's public API.

beginner

How do you declare an explicit interface implementation in C#?

Use the interface name followed by a dot before the member name, for example: void IInterface.Method().

beginner

Can you call an explicitly implemented interface method directly from a class instance?

No, you must cast the class instance to the interface type first to call the method.

intermediate

What happens if two interfaces have methods with the same signature and you implement them explicitly?

You can provide separate implementations for each interface method, avoiding conflicts and clarifying which method belongs to which interface.

How do you call an explicitly implemented interface method from a class instance obj?

A obj->Method()

B obj.Method()

C ((InterfaceType)obj).Method()

D InterfaceType.Method(obj)

Explicit interface methods are only accessible through the interface, so you must cast the object to the interface type first.

Which syntax correctly declares an explicit interface implementation for method Show() in interface IDisplay?

A void IDisplay.Show()

B public void Show()

C IDisplay.Show()

D public IDisplay.Show()

Explicit interface implementation uses the interface name followed by a dot before the method name without an access modifier.

What is a main benefit of explicit interface implementation?

A It allows hiding interface methods from the class's public API

B It automatically implements all interface methods

C It makes interface methods public by default

D It allows interface methods to be static

Explicit implementation hides the interface methods from the class's public interface, making them accessible only through the interface.

If a class implements two interfaces with the same method name, how can explicit implementation help?

A By merging both methods into one

B By providing separate implementations for each interface method

C By ignoring one interface method

D By renaming the class

Explicit implementation allows separate method bodies for each interface method, avoiding conflicts.

Which statement is true about explicit interface implementation?

A Explicit interface methods can be called without casting

B Explicit interface methods are inherited by derived classes

C Explicit interface methods cannot be private

D Explicit interface methods do not have access modifiers

Explicit interface implementations do not have access modifiers like public or private; they are implicitly private and accessible only via the interface.

Explain how explicit interface implementation works and why you might use it.

Think about how to keep interface methods separate from class methods.

Describe how to call an explicitly implemented interface method from an object instance.

Remember explicit methods are hidden from the class itself.