ArcGISRuntimeXamarin.Samples.OpenMapOAuth.OpenMapOAuth.OnLoadMapClicked C# (CSharp) 메소드

        private async void OnLoadMapClicked(object sender, EventArgs e)
        {
            // Challenge the user for portal credentials
            CredentialRequestInfo loginInfo = new CredentialRequestInfo();

            // Use the OAuth implicit grant flow
            loginInfo.GenerateTokenOptions = new GenerateTokenOptions
            {
                TokenAuthenticationType = TokenAuthenticationType.OAuthImplicit
            };

            // Indicate the url (portal) to authenticate with 
            loginInfo.ServiceUri = new Uri(PortalUrl);

            try
            {
                // Get a reference to the (singleton) AuthenticationManager for the app
                AuthenticationManager thisAuthenticationManager = AuthenticationManager.Current;

                // Call GetCredentialAsync on the AuthenticationManager to invoke the challenge handler
                await thisAuthenticationManager.GetCredentialAsync(loginInfo, false);

                // Access the portal
                ArcGISPortal portal = await ArcGISPortal.CreateAsync(new Uri(PortalUrl));

                // Get the item (web map) from the portal
                PortalItem item = await PortalItem.CreateAsync(portal, WebMapId);

                // Make sure it's a web map
                if (item.Type != PortalItemType.WebMap)
                {
                    return;
                }

                // Display the web map in the map view
                Map webMap = new Map(item);
                _myMapView.Map = webMap;
            }
            catch (System.OperationCanceledException)
            {
                // User canceled the login
                var alertBuilder = new AlertDialog.Builder(this);
                alertBuilder.SetTitle("Cancel");
                alertBuilder.SetMessage("Portal login was canceled.");
                alertBuilder.Show();
            }
            catch(Exception ex)
            {
                // Other exception
                var alertBuilder = new AlertDialog.Builder(this);
                alertBuilder.SetTitle("Error");
                alertBuilder.SetMessage(ex.Message);
                alertBuilder.Show();
            }
        }