如何将未绑定的回调包装为异步函数

Question

I have to use external component which consist of setting callback "onReceiveData" first to a single method. Then whenever I call sendData I process result in setted method. I'm come from javascript world and I am very confused how to process such request in MVC controller where I need to call the function, wait for response and return results in View. Is there some easy way to wrap it to asynchronous method to use async/await?

var component = new Component();
component.Server = "10.0.0.1:30";
component.RecvData = new Component.RecvDataCB(someMethod);
component.start();
component.SendDate(data);

Answer 1

It would be nice to see whole context but for now I'm not sure what you are looking for. I see two questions ( maybe even three ).

1. How to process such request in MVC controller where I need to call the function, wait for response and return results in View
2. Is there some easy way to wrap it to asynchronous method to use async/await?

Let's begin.

1. Let's imagine you have controller and an action which returns a view. But not just a view but also a data with it - ViewModel. One thing that you need to do, if we talking about MVC, is to tell your View how to handle or work with ViewModel that it's getting. For this we need specify a @Model and name

Controller:

public class HomeController : Controller
    {
        public IActionResult Index()
        {
            var model = new UserViewModel();
            return View(model);
        }
    }

ViewModel:

public class UserViewModel
{
    public string Name { get; set; }
    public int Age { get; set; }
}

View:

@model UserViewModel

<div class="text-center">
    <p>@Model.Name</p>
    <p>@Model.Age</p>
</div>

2. If you want to make your methods async the return type of method should be Task<T> . So let's image you have class( same ViewModel. NOTICE never ever keep business logic in viewModel. ) but instead just properties you have some methods inside.

ViewModel:

public class UserViewModel
    {
        public string Name { get; set; }
        public int Age { get; set; }

        public UserViewModel(int age, string name)
        {
            this.Age = age;
            this.Name = name;
        }

        public async Task<int> GetAge()
        {
            return this.Age;
        }


        public async Task<string> GetName()
        {
            return this.Name;
        }

    }

Since your methods' return type is Task they can be async and await 'ed. You controller would look like this.
Controller:

public class HomeController : Controller
    {
        public async Task<IActionResult> Index()
        {
            var model = new UserViewModel(16,"Bob");
            string name = await model.GetName();
            int age = await model.GetAge();
            return View(model);
        }
    }