Xamarin表单-Android线程

Question

I am implementing web API services using Xamarin Forms and MVC API .net. I have created Auth services and I can get an access token using Postman app. If I run my project on UWP platform, the app works fine, I can get user a token to access web API. However, whenever I run the app on Android platform, I get an unhandled exception that stating of "36 frames are skipped. The application may be doing too much work on its main thread". I am using Async ... Await methods and still getting this error. Could you please advise me how can I avoid this error? Thank you!

Here are my codes:

ApiServices:

public class ApiServices {
    public async Task RegisterUserAsync(string email, string password, string confirmPassword) {
        var client = new HttpClient();
        var success = false;
        var model = new RegisterBindingModel {
            Email = email, Password = password, ConfirmPassword = confirmPassword
        };
        try {
            var json = JsonConvert.SerializeObject(model);
            HttpContent content = new StringContent(json);
            content.Headers.ContentType = new MediaTypeHeaderValue("application/json");
            if (email != null || password != null) {
                success = true;
                Acr.UserDialogs.UserDialogs.Instance.ShowSuccess(string.Format("You are now signed-in as {0}.", email));
                var response = await client.PostAsync(Constants.BaseApiAddress + "api/Account/Register", content);
                Debug.WriteLine(response);
                Debug.WriteLine(await response.Content.ReadAsStringAsync());
                Debug.WriteLine(response.StatusCode);
            }
        } catch (Exception ex) {
            //Acr.UserDialogs.UserDialogs.Instance.ShowError(string.Format("Authentication Failed: {0}", ex.Message));
        }
    }
}

LoginViewModel:

public class LoginViewModel {
        public string Email {
            get;
            set;
        }
        public string Password {
            get;
            set;
        }
        public ICommand LoginCommand {
            get {
                return new Command(async() => {
                    ApiServices apiServices = new ApiServices();
                    await apiServices.LoginUserAsync(Email, Password);
                });
            }
        }
    }

Answer 1

Async/await keyword offer asynchronous support, but if this is used in UI thread they can hurt performance. So to improve UI experience, excute the code in another thread, like said @SushiHangover, with Task.Run().

LoginViewModel:

public class LoginViewModel {
    public string Email {
        get;
        set;
    }
    public string Password {
        get;
        set;
    }
    public ICommand LoginCommand {
        get {
            return new Command(async() => {
                ApiServices apiServices = new ApiServices();
                await Task.Run(() => {
                    apiServices.LoginUserAsync(Email, Password);
                });
        }
    }
}