What is Encapsulation in C#?
💡 Concept: Encapsulation in C#
Encapsulation is an object-oriented principle in C# where the internal state of an object is hidden from the outside, and access is controlled through public interfaces like methods or properties.
📘 Quick Intro
By using access modifiers such as private, public, and protected, encapsulation helps prevent unintended interference with object internals, leading to more secure and maintainable code.
🧠 Analogy
Think of a capsule of medicine—it contains powerful contents but only exposes what's needed to heal. In the same way, a class hides complex logic and exposes only what’s required using controlled access points.
🔧 Technical Explanation
- ✔️ Fields are marked
privateto restrict direct access. - ✔️ Public methods or properties allow safe and validated interaction.
- ✔️ Encapsulation ensures class invariants are maintained.
- ✔️ It promotes code refactoring without affecting dependent code.
🎯 Use Cases
- 🔒 Secure class fields from unexpected changes.
- ✅ Validate input using setters or methods.
- 🔁 Change internal implementation without affecting external use.
- 📦 Package class logic in reusable and robust components.
💻 Real Code Example
public class BankAccount
{
private decimal balance;
public void Deposit(decimal amount)
{
if (amount > 0)
balance += amount;
}
public decimal GetBalance()
{
return balance;
}
}
❓ Interview Q&A
Q1: What is encapsulation?
A: It's a principle of hiding internal class details and exposing only necessary parts.
Q2: How is encapsulation achieved in C#?
A: Through access modifiers and property wrappers.
Q3: Why is encapsulation important?
A: It protects internal state and reduces system complexity.
Q4: Can we access private fields directly?
A: No, they are only accessible inside the class.
Q5: What’s the benefit of using properties over public fields?
A: Properties provide control, validation, and future flexibility.
Q6: What happens if encapsulation is not used?
A: The code becomes fragile, error-prone, and harder to maintain.
Q7: What access modifier is best for sensitive data?
A: private or protected.
Q8: What is a property in C#?
A: A property is a method-like member used to encapsulate a field.
Q9: Can a method be used for encapsulation?
A: Yes, methods provide controlled behavior around private state.
Q10: What is information hiding?
A: Another name for encapsulation—hiding internal implementation details.
📝 MCQs
Q1. What does encapsulation protect?
- User input
- Class name
- Internal data of the object
- Console output
Q2. Which modifier hides class members?
- public
- static
- sealed
- private
Q3. What is the advantage of encapsulation?
- Slower code
- Complex access
- Better control and maintainability
- Open access to internals
Q4. What helps enforce encapsulation?
- Inheritance
- Interfaces
- Properties
- Events
Q5. Which principle enables hiding implementation?
- Abstraction
- Encapsulation
- Polymorphism
- Delegates
Q6. Which access modifier exposes data publicly?
- private
- public
- internal
- protected
Q7. Which method type helps modify private data?
- Private getter
- Public setter
- Abstract method
- Event handler
Q8. Encapsulation improves what aspect of software?
- Color scheme
- Runtime speed
- Robustness
- Package size
Q9. Is encapsulation only about hiding data?
- Yes
- No, also controlling access
- Only in Java
- Only UI-related
Q10. Why avoid public fields?
- They are slower
- No IntelliSense
- Lack of control and validation
- Compiler errors
💡 Bonus Insight
Encapsulation is not just a concept but a habit that leads to cleaner APIs, safer interactions, and better separation of concerns. It's the silent guard of your class design.
📄 PDF Download
Need a handy summary for your notes? Download this topic as a PDF!