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c#lambdadelegatesanonymous-function
Jiew Meng
Jiew Meng

Reputation: 88189

Delegates, Lambdas, Action, Func, Anonymous Functions

I just want to verify my understanding about the following

hmm... they all do similar things, how do you define & know when to use each?

sorry, I don't explain well

Upvotes: 5

Views: 1908

Answers (3)

Unmesh Kondolikar
Unmesh Kondolikar

Reputation: 9312

  • Delegate - it is not a method signature. It is a type which encapsulates a method. Hence a delegate declaration should have a signature similar to the method it wants to encapsulate. When to use Delegate - whenever you want to pass a method to another function. For more see this and this.

  • Lambdas - short hand and more expressive way of writing an anonymous function. But there is more to it. A lambda expression can also be converted to an expression tree. For more see this.

  • Anonymous Function - yes .. just that

  • Action - It is a delegate which can encapsulate a function that returns nothing. So you should think of it as a type that can encapsulate an action and use it when you need to pass an action around.

  • Func - A delegate that can encapsulate a function that returns something. But you should look at it as a type that can encapsulate a transformation and use when you want to pass around a transformation.

Upvotes: 9

alpha-mouse
alpha-mouse

Reputation: 5003

Action and Func are just special cases of the Delegate. Delegate itself is something that references a method and can be used to call it.

Upvotes: 4

Jack
Jack

Reputation: 133557

Don't try to see C# + these features. Also because there is not a strict pragmatic answer to your question.

Start from a functional programming point of view, for example try to learn F# to get inside what and when lambdas are used (actually everywhere inside a functional language) and then you'll understand things better.

It will open your mind and make you think differently about imperative programming or mixed languages like C#.

Upvotes: 3

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