Is there a way to cast Func to Func given I know v1 and v2?

Question

So I have this function that takes a function with no parameters:

public static bool RetryUntilSuccessOrTimeout(Func<bool> task, TimeSpan timeSpan)
    {
        bool success = false;
        int elapsed = 0;
        while ((!success) && (elapsed < timeSpan.TotalMilliseconds))
        {
            Thread.Sleep(1000);
            elapsed += 1000;
            success = task();
        }
        return success;
    }

And then I have a bunch of functions like:

private static bool OnDeleted(object source, FileSystemEventArgs e){...}
private static bool OnChanged(object source, FileSystemEventArgs e){...}
private static bool OnCreated(object source, FileSystemEventArgs e){...}

I have a function that takes same aruments as those three. So I have that information provided. Is there a way to pass these function as ones not taking any arguments (because I provide them) so i can pass it into the "task" of RetryUntilSuccessOrTimeout() ?

An encapsulating image of the problem:

OnDirEvent

Iam innerly cringing when I see any func called like this. In your situation its ok, when the func is null you probably want to raise an exception. I habitly call these by `task?.Invoke() ?? true` when a plausible default is at hand. Otherwise handle null ref in place / upstream. — Patrick Artner, Jan 10 '18 at 16:07

score 3 · Accepted Answer · answered Jan 10 '18 at 16:04

3

Yes. Basically you just do

() => func(a, b)

answered Jan 10 '18 at 16:04

Adam Brown

1,667
7
9

1

What you want is called "partial function application". C# doesn't have language-level support for it like some languages (F#, Haskell), but using lambda expressions works in some cases. – JamesFaix Jan 10 '18 at 16:06
@stt106 No, it's not. It's partial function application, as was mentioned in the previous comment. Currying that function would be taking a `Func – Servy Jan 10 '18 at 16:12

Is there a way to cast Func to Func given I know v1 and v2?

1 Answers1