在一个 object 上执行多个异步 function

Question

I'm curious is it possible to execute function Function1 and function Function2 in C# webapi project like in example below.

Both of these functions are on the same class and use async and await but return different types.

Example code below:

[ApiController]
[Route("[controller]")]
public class ClassController : ControllerBase
{
    // ...
    public async Task<ActionResult<string>> Test()
    {
        var message = await _myClass.Function1().Function2();
        return Ok(message);
    }
    // ...
}

Declaration of _myClass looks like below:

public class MyClass
{
    // ...
    public async Task<MyClass> Function1()
    {
        // code which uses `await` below
        // ....
        // end of this code
        return this;
    }
    public async Task<string> Function2()
    {
        // code which uses `await` below
        // ....
        // end of this code
        return "some text";
    }
}

Answer 1

Yes, you can do this:

public async Task<ActionResult<string>> Test()
{
    var message = await
        _myClass.Function1().ContinueWith(resultingMyClass => 
        resultingMyClass.Result.Function2());
    return Ok(message);
}

But the most obvious solution would be to use the async/await syntax that C# provides:

public async Task<ActionResult<string>> Test()
{
    var result1 = await _myClass.Function1();
    var message = await result1.Function2();

    return Ok(message);
}

If you don't need the result from the first call as input to the second function you can run multiple Tasks in parallel and wait until they have all finished using Task.WhenAll .