Asynchronously calling an async method

Problem

I have a method that is asynchronous:

public async Task<string> GenerateCodeAsync()
{
    string code = await GenerateCodeService.GenerateCodeAsync();
    return code;
}

This is a synchronous method that I need to call.

How can I accomplish this without duplicating the GenerateCodeAsync method in order for it to work synchronously?

Update

Despite this, no suitable remedy has been identified.

HttpClient, on the other hand, appears to have already implemented this approach.

using (HttpClient client = new HttpClient())
{
    // async
    HttpResponseMessage responseAsync = await client.GetAsync(url);

    // sync
    HttpResponseMessage responseSync = client.GetAsync(url).Result;
}

Asked by Catalin

Solution #1

The task’s Result property can be accessed, causing your thread to block until the result is available:

string code = GenerateCodeAsync().Result;

Note that this may result in a stalemate in some cases: The main thread is blocked by your call to Result, which prevents the rest of the async code from running. To prevent this from happening, you have the following options:

This isn’t to say that you should just add without thinking. After all your async calls, call ConfigureAwait(false). For a more in-depth look at why and when you should use. See the following blog article for more information about ConfigureAwait(false):

Answered by Heinzi

Solution #2

Get the awaiter (GetAwaiter()) and end the wait for the asynchronous job to complete (GetResult()).

string code = GenerateCodeAsync().GetAwaiter().GetResult();

Answered by Diego Torres

Solution #3

You should be able to accomplish this with the help of delegates. expression lambda

private void button2_Click(object sender, EventArgs e)
    {

        label1.Text = "waiting....";

        Task<string> sCode = Task.Run(async () =>
        {
            string msg =await GenerateCodeAsync();
            return msg;
        });

        label1.Text += sCode.Result;

    }

    private Task<string> GenerateCodeAsync()
    {
        return Task.Run<string>(() => GenerateCode());
    }

    private string GenerateCode()
    {
        Thread.Sleep(2000);
        return "I m back" ;
    }

Answered by Faiyaz

Solution #4

GenerateCodeAsync makes it possible (). GenerateCodeAsync or Result (). As the other answer indicates, you can use wait(). Until GenerateCodeAsync completes, the current thread will be blocked.

Your query, however, is tagged with asp.net, and you also added the following comment:

My argument is that in ASP.NET, you should never block on an asynchronous procedure. This will reduce your web app’s scalability and may result in a stalemate (when an await continuation inside GenerateCodeAsync is posted to AspNetSynchronizationContext). Using the Task Run(…). Since a result of offloading anything to a pool thread and then blocking, the scalability would be harmed even more, as each HTTP request will require +1 more thread to execute.

Asynchronous methods are built-in to ASP.NET, either through asynchronous controllers (in ASP.NET MVC and Web API) or directly through AsyncManager and PageAsyncTask in classic ASP.NET. You should make use of it. Check out this response for further information.

Answered by noseratio

Solution #5

Microsoft Identity offers extension methods that synchronously invoke async methods. There’s a GenerateUserIdentityAsync() function, for example, and a CreateIdentity() method ()

If you look into UserManagerExtensions, you’ll see what I mean. It looks like this: CreateIdentity()

 public static ClaimsIdentity CreateIdentity<TUser, TKey>(this UserManager<TUser, TKey> manager, TUser user,
        string authenticationType)
        where TKey : IEquatable<TKey>
        where TUser : class, IUser<TKey>
    {
        if (manager == null)
        {
            throw new ArgumentNullException("manager");
        }
        return AsyncHelper.RunSync(() => manager.CreateIdentityAsync(user, authenticationType));
    }

Let’s have a look at AsyncHelper. RunSync is a program that allows you to sync your

  public static TResult RunSync<TResult>(Func<Task<TResult>> func)
    {
        var cultureUi = CultureInfo.CurrentUICulture;
        var culture = CultureInfo.CurrentCulture;
        return _myTaskFactory.StartNew(() =>
        {
            Thread.CurrentThread.CurrentCulture = culture;
            Thread.CurrentThread.CurrentUICulture = cultureUi;
            return func();
        }).Unwrap().GetAwaiter().GetResult();
    }

So, this is your async method wrapper. Also, don’t read data from Result if you don’t want your ASP code to get stuck.

There is another option, which I find suspect, but you can consider it as well.

  Result r = null;

            YourAsyncMethod()
                .ContinueWith(t =>
                {
                    r = t.Result;
                })
                .Wait();

Answered by Vitaliy Markitanov

Post is based on https://stackoverflow.com/questions/22628087/calling-async-method-synchronously