How do I call ForceClient.UserInfo() synchronously

Question

I'm converting the data access layer of an old app from MySql to Salesforce using WinForms, DeveloperForce, Visual Studio 2015, .Net 4.6.1, C#. This is my first real TPL/async/await project.

I'm stuck on how to call ForceClient.UserInfo synchronously.

Anyway, this works:

public ForceClient Connect(){
    if (_forceClient == null){
        _auth = new AuthenticationClient();
        _auth.UsernamePasswordAsync(...).Wait();
        _forceClient = new ForceClient(_auth.InstanceUrl, _auth.AccessToken, _auth.ApiVersion);
    }
    return _forceClient;
}
...
private async Task<int> GetSomeData(){
    var response = await Force.Connect().QueryAsync<dynamic>("SELECT...").ConfigureAwait(false);
    //load data to local storage
    return response.Count
}

So far so good - The connect() blocks the first time until it connects, then I send all my queries at once and load them in pseudo parallel as the results are returned. Yay. Now I want to add a synchronous call to ForceClient.UserInfo() toward the end of the connect method.

This works asyncronously:

userInfo = await _forceClient.UserInfo<UserInfo>(UserInfoEndpointUrl);

But all my attempts to call it synchronously have failed. I've tried .Wait(), .RunSynchronously(), Task.WaitAll, Task.WaitAny, ConfigureAwait(false),... Most things I try end up causing the call to hang indefinitely (thread deadlock)

Help? Thanks!

Answer 1

Update based on comments.

You need to use Task.ConfigureAwait(false); to prevent blocking the UI thread context.

See Don't Block on Async Code

---

I made the call synchronously using the following:

class Program
{
    static void Main(string[] args)
    {
        Task.Run(async () =>
        {
            MainAsync(args);
        }).Wait();

        Thread.Sleep(1000);
        Console.WriteLine("Done");
    }

    static async Task MainAsync(string[] args)
    {
        try
        {
            var auth = new AuthenticationClient();
            auth.UsernamePasswordAsync("ConsumerName", "ClientSecret", "[email protected]", "password goes here").Wait();

            var forceClient = new ForceClient(auth.InstanceUrl, auth.AccessToken, auth.ApiVersion);

            // Without the Thread.Sleep above the application will often close before the result comes back.
            //var userInfo = await forceClient.UserInfo<UserInfo>(auth.Id);
            //Console.WriteLine(userInfo.FirstName);

            var task = forceClient.UserInfo<UserInfo>(auth.Id);
            task.Wait();
            var userInfo2 = task.Result;
            Console.WriteLine(userInfo2.FirstName);
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
        }
    }
}

If I made the call asynchronously and didn't have the Thread.Sleep(1000) the application would close before the UserInfo came back.

Note that the usage of Task.Wait and Task.Result isn't ideal as an exception within the Task will be wrapped in an AggregateException.

See also:

• How to call asynchronous method from synchronous method in C#?
• Async/Await - Best Practices in Asynchronous Programming