Making a login method in Xamarin.forms - asp.net-web-api

Question

Once the user submits the login info, and presses login button the following method is called;
public Page OnLogInButtonClicked (string email, string password)
{
var client = new RestClient("http://babyAPI.com");
var request =
new RestRequest("api/ApiKey?email=" + email + "&password=" + password, Method.GET);
var queryResult = client.Execute(request);
if (queryResult.StatusCode == HttpStatusCode.OK)
{
var deserial = new JsonDeserializer();
var x = deserial.Deserialize<ApiKey>(queryResult);
return;
}
else
{
return;
}
}
Is this the correct way to do it? And if the user is authenticated, I need to navigate to a new page, else show authentication failed. How can that be done?

Answer 1

Your question is quite broad. What are you looking to solve?
Here's what I think can be improved in this code. Assuming this is a ViewModel class - if it isn't read up on MVVM in Xamarin. I'd suggest also reading up on Separation of Concerns (also see the links on the bottom about DRY and Single Responsibility)
// make the method async so your UI doesn't lock up
public async Task AuthenticateAndNavigate(string email, string pass){
// your MVVM framework may have IsBusy property, otherwise - define it
// it should be bindable so you can use it to bind activity indicators' IsVisible and buttons' IsEnabled
IsBusy = true;
try{
// split out the code that talks to the server in a separate class - don't mix UI, ViewModel and server interactivity (separation of concerns principle)
// the assumption here is that a null is returned if auth fails
var apiKey = BabyApi.GetApiKey(email, pass);
// the Navigation property below exists in some MVVM frameworks, otherwise it comes from a Page instance that calls this code
if (apiKey!=null)
await Navigation.PushModalAsync(new HomePage());
else
await Navigation.PushAsync(new FailedToAuthenticatePage()); // or just do nothing
} catch {
await Navigation.PushAsync(new FailedToAuthenticatePage { Error: x.Message });
} finally {
IsBusy = false;
}
}