CODEWITHSUNDEEP
c#delegatesaction
sourcenouveau
sourcenouveau

Reputation: 30514

Traditional loop versus Action delegate in .NET

After learning about the Action delegate in C# I've been looking for ways I can best use it in my code. I came up with this pattern:

Action<string> DoSomething = (lSomething) =>
{
    // Do something
};

DoSomething("somebody");
DoSomething("someone");
DoSomething("somewhere");

If I were to have used a traditional loop, it would look something like this:

List<string> lSomeList = new List<string>();
lSomeList.Add("somebody");
lSomeList.Add("someone");
lSomeList.Add("somewhere");

foreach (string lSomething in lSomeList)
{
    // Do something
}

Are there any appreciable differences between the two? To me they look equally easy to understand and maintain, but are there some other criteria I might use to distinguish when one might be preferred over the other?

Upvotes: 1

Views: 883

Answers (3)

usr
usr

Reputation: 171188

There is an advantage to the first pattern that does not come up with loops. Example:

Action<string> DoSomething = (lSomething) =>
{
    // Do something
};

DoSomething("somebody");

if (b) DoSomething("somebody2");
else while (F()) DoSomething("somebody3")

...

So you see the lambda version is more flexible because it can be invoke in mutiple places, not only in one place.

Upvotes: 0

Jon Skeet
Jon Skeet

Reputation: 1500375

If you need to be able to pass the action from one piece of code to another, it's really nice to wrap it up in a delegate.

If you need the same action in slightly different contexts within the same method, a delegate is one option - although extracting it into a different method may make more sense, depending on the situation.

Usually I would just go for executing the code directly though. The example you've given isn't particularly realistic IMO - usually you'd have a list either way and either call List<T>.ForEach or use a plain foreach loop - at which point I'd favour the foreach loop for the same reasons that Eric Lippert gives in the blog post Anthony linked to.

Upvotes: 4

Anthony Pegram
Anthony Pegram

Reputation: 126834

The fact that you have three method calls versus a loop and a single method (or simply a loop body) would be enough to make me reconsider.

Semi-related, perhaps read this blog and see if that gives you a different perspective. http://blogs.msdn.com/ericlippert/archive/2009/05/18/foreach-vs-foreach.aspx

Upvotes: 3

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