What are Anonymous Methods in C#?

Q: What is an anonymous method in C#?

An anonymous method is a method without a name, defined inline using the delegate keyword.

Q: Can anonymous methods access outer variables?

Yes, they support closures and can use variables from their outer scope.

💡 Concept: Anonymous Method

An anonymous method in C# is a method without a name, defined inline using the delegate keyword. It can be assigned to a delegate and executed like a normal method.

📘 Quick Intro

Anonymous methods provide a convenient way to define inline code blocks for short delegate implementations without declaring a separate method. Introduced in C# 2.0, they are often used for event handling and callbacks.

🧠 Analogy

Imagine a sticky note with instructions. You don’t give the note a title, you just write the steps. That’s like an anonymous method — no formal name, but it does the job right when needed.

🔧 Technical Explanation

⚙️ Anonymous methods are defined using the delegate keyword without a name.
🚫 Cannot have access modifiers or overloads.
🎯 Typically used to reduce verbosity in event handlers or callbacks.
✅ Can access outer method variables (closures).
🔄 Often replaced by lambda expressions in modern C#.

🎯 Use Cases

✅ Defining inline event handlers for UI actions.
✅ One-off delegate usage for short logic blocks.
✅ Improving code readability by reducing boilerplate.
✅ Simplifying logic in LINQ queries or threading scenarios.

💻 Code Example

public delegate void PrintDelegate(string message);

class Program {
    static void Main() {
        PrintDelegate print = delegate(string msg) {
            Console.WriteLine(""Anonymous says: "" + msg);
        };

        print(""Hello from anonymous method!"");
    }
}

❓ Interview Q&A

Q1: What is an anonymous method?
A: A method defined inline without a name using the delegate keyword.

Q2: Can anonymous methods access outer variables?
A: Yes, they support closures.

Q3: In which version of C# were anonymous methods introduced?
A: C# 2.0.

Q4: Can you use parameters in anonymous methods?
A: Yes, they can accept parameters like named methods.

Q5: Are anonymous methods the same as lambda expressions?
A: No, but they are similar and often replaced by lambdas.

Q6: Can anonymous methods return values?
A: Yes, if the delegate signature returns a value.

Q7: Can you use async in anonymous methods?
A: Yes, with lambda syntax.

Q8: Are anonymous methods useful for event handling?
A: Yes, they are ideal for inline event handling.

Q9: Can anonymous methods be removed from event subscriptions?
A: No, they cannot be easily removed unless assigned to a variable.

Q10: Do anonymous methods have access modifiers?
A: No, access modifiers aren’t allowed.

📝 MCQs

Q1. Which C# version introduced anonymous methods?

C# 1.0
C# 2.0
C# 3.0
C# 4.0

Q2. Which keyword is used to define an anonymous method?

lambda
var
delegate
method

Q3. Can anonymous methods have names?

Yes
No
Optional
Only in lambdas

Q4. What is a common replacement for anonymous methods in modern C#?

Named functions
Partial classes
Lambda expressions
Events

Q5. Can anonymous methods be used with delegates?

Yes
No
Only with events
Only with generics

Q6. What is a closure in C#?

A sealed class
A virtual method
Anonymous method accessing outer variables
An async callback

Q7. Can anonymous methods return values?

No
Yes
Only void
Only from lambdas

Q8. Can anonymous methods be async?

No
Yes, with lambdas
Only static methods
Only void

Q9. Which keyword cannot be used with anonymous methods?

delegate
return
public
string

Q10. Are anonymous methods useful for event handling?

No
Yes
Only in UI
Rarely

💡 Bonus Insight

Anonymous methods make your code more concise and readable when the logic is short-lived and doesn't require reuse. In modern C#, lambda expressions are preferred for this purpose, but understanding anonymous methods helps you grasp delegate fundamentals.

📄 PDF Download

Need a handy summary for your notes? Download this topic as a PDF!

📄 PDF Download Coming Soon