这个语法是什么意思？ FUNC <Task, TResult> sampleFunction

Question

I have been using Task.Factory.ContinueWhenAny() for while and just decided to examine other options. So I referred to it's MSDN reference page and the syntax for this commands is described as:

public Task<TResult> ContinueWhenAny<TResult>(
    Task[] tasks,
    Func<Task, TResult> continuationFunction,
    CancellationToken cancellationToken
)

It's clear to me that the parts mentioned inside < & > are types , such as the expected return value of a type TResult in Task<TResult> . However I am not quite sure what this part of this syntax would mean:

Func<Task, TResult> continuationFunction

As you can see there are two parameters sandwiched inside <> and separated by a comma.

Answer 1

It's a Func delegate and it's declared like this:

public delegate TResult Func<in T, out TResult>(T arg);

It represents a function that takes a Task parameter and returns a result of type TResult .

It is similar to:

TResult ContinuationFunction<T,TResult>(T arg) { ... }

Further reading

• Generics
• Delegates
• Func<T, TResult> Delegate