Delegates in C# | Delegates Part 1 | C#.NET Tutorial | Mr. Bangar Raju

Summary

In this video, the host, Bangar Raju, introduces the concept of delegates in C# programming. He explains that a delegate is a type-safe function pointer that holds a reference to a method and executes it. The video demonstrates how to define, instantiate, and use delegates to call methods, both static and non-static. The process involves defining a delegate with a matching method signature, instantiating the delegate with a method reference, and then invoking the method through the delegate. The video aims to clarify the advantages of using delegates for method invocation in C#.

Takeaways

• 😀 Delegates in C# are a type-safe function pointer, holding a reference to a method and invoking it.
• 🔑 The definition of a delegate closely resembles a method signature, differing only by the use of the 'delegate' keyword.
• 📝 Defining a delegate requires matching the return type and parameter types exactly with the method it references.
• 📌 Delegates are reference types, similar to classes, structures, and interfaces, and are defined within namespaces.
• 🛠 To call a method using a delegate, one must first define the delegate, then instantiate it with a method, and finally invoke the delegate.
• 👉 Instantiating a delegate involves creating an instance and associating it with a method that matches the delegate's signature.
• 💡 Delegates allow for methods to be called dynamically, providing flexibility in executing methods without direct calls.
• 🎯 The 'invoke' method is a built-in way to execute the method referenced by a delegate, offering an alternative to direct delegate invocation.
• 🔄 Understanding delegates is crucial for advanced C# programming, including event handling and callbacks.

Q & A

What is a delegate in the context of the video?

A delegate is a type-safe function pointer that holds a reference to a method and can call that method for execution.

Why are delegates used in programming?

Delegates are used to call methods in a more flexible way, allowing for dynamic method invocation and event handling.

How can you call a non-static method using a delegate?

To call a non-static method using a delegate, you first need to create an instance of the class, then instantiate the delegate with the method, and finally call the delegate with the required parameters.

What is the difference between calling a method directly and using a delegate?

Calling a method directly involves invoking it through an instance or class name, while using a delegate involves defining, instantiating, and then calling the delegate with the method as a parameter.

What are the two important points to remember when defining a delegate for a method?

When defining a delegate for a method, the return type of the delegate should match the return type of the method, and the parameter types of the delegate should match the parameter types of the method.

Can a delegate be defined inside a class?

Yes, a delegate can be defined inside a class, but it is generally advised to define it under a namespace to follow best practices.

What is the purpose of the 'invoke' method in a delegate?

The 'invoke' method in a delegate is used to call the method that the delegate is pointing to, with the provided parameters.

How does the video demonstrate the instantiation of a delegate?

The video demonstrates the instantiation of a delegate by creating an instance of the delegate and passing the method name as a parameter to the delegate constructor.

What is the significance of matching the delegate signature with the method signature?

Matching the delegate signature with the method signature ensures that the delegate can correctly reference and call the method, as it guarantees that the types of parameters and the return type are compatible.

Why is it important for a non-static method to be accessed through an instance when instantiating a delegate in a static context?

A non-static method must be accessed through an instance because it is associated with a specific object state, and a static context does not have direct access to instance-specific data.