Task return type with and without Async [duplicate]

Question

I little bit confused on the behavior of the async keyword.

Lets say I have 2 methods,

public async Task DoSomething1()
{
    await Task.Run(() =>
    {
        for(int i = 0; i<3; i++)
        {
            Console.WriteLine("I m doing something:" + i);
        }
    });
}

And

public Task DoSomething2()
{
    return Task.Run(() =>
    {
        for(int i = 0; i<3; i++)
        {
            Console.WriteLine("I m doing something:" + i);
        }
    });
}

From my understanding both methods are awaitable. But when I write a method that has a Task return type without the async keyword I need to return a Task otherwise the compiler generates an error. Its a common thing that a method should return its type. But when I use it with the async keyword the compiler generates another error that you can't return a Task. So what does it mean? I am totally confused here.

Answer 1

If you use await in your code, you are required to use the async keyword on the method.

If you use async and want to return an actual type, you can return the type as a generic Task like this Task<int>.

Here are the valid return types for an async method:

https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/concepts/async/async-return-types

1. Task<TResult>, for an async method that returns a value.
2. Task, for an async method that performs an operation but returns no value.
3. void, for an event handler.