Authenticate windows 10 app with Azure AD (WAM)

Technology: Windows 10 Apps, Azure AD, WAM

Required Name Spaces:

using System;
using System.Linq;
using System.Threading.Tasks;
using Windows.Security.Authentication.Web;
using Windows.Security.Authentication.Web.Core;
using Windows.Security.Credentials;

        
        public static string AdalClientId = App.clintID; //clientID from Azure AD
        public static string AdalResourceId = App.ServiceResourceUrl; // Web api Service appID from Azure AD
        const string MicrosoftAccountProviderId = "https://login.microsoft.com";
        public string AdalIssuerAuthority = "https://login.windows.net/contoso.onmicrosoft.com";
        
        string URI = string.Format("ms-appx-web://Microsoft.AAD.BrokerPlugIn/{0}", WebAuthenticationBroker.GetCurrentApplicationCallbackUri().Host.ToUpper()); //URI need to enter while registering into Azure AD
        string szReturnUri = WebAuthenticationBroker.GetCurrentApplicationCallbackUri().AbsoluteUri;
        AuthenticationResult AResult;
        public async Task<string> Authenticate(bool prompt)
        {
            WebAccountProvider provider = await WebAuthenticationCoreManager.FindAccountProviderAsync(MicrosoftAccountProviderId, AdalIssuerAuthority);

            try
            {
                WebTokenRequest webTokenRequest = new WebTokenRequest(provider, "", AdalClientId);

                // webTokenRequest.Properties.Add("resource", "https://graph.windows.net");
                webTokenRequest.Properties.Add("resource", App.ServiceResourceUrl);

                // If the user selected a specific account, RequestTokenAsync will return a token for that account.
                // The user may be prompted for credentials or to authorize using that account with your app
                // If the user selected a provider, the user will be prompted for credentials to login to a new account
                WebTokenRequestResult webTokenRequestResult;
                if (prompt)
                {
                    webTokenRequestResult = await WebAuthenticationCoreManager.RequestTokenAsync(webTokenRequest);


                    ////result = await context.AcquireTokenAsync(AdalResourceId, AdalClientId, _returnUri, PromptBehavior.Auto, objUserIdtfr, "domain_hint=microsoft.com");
                }
                else
                {
                    webTokenRequestResult = await WebAuthenticationCoreManager.GetTokenSilentlyAsync(webTokenRequest);
                }
                // If a token was successfully returned, then store the WebAccount Id into local app data
                // This Id can be used to retrieve the account whenever needed. To later get a token with that account
                // First retrieve the account with FindAccountAsync, and include that webaccount 
                // as a parameter to RequestTokenAsync or RequestTokenSilentlyAsync
                if (webTokenRequestResult.ResponseStatus == WebTokenRequestStatus.Success)
                {
                  
                    App.AccessToken = webTokenRequestResult.ResponseData[0].Token;

                    string szUserinfo = webTokenRequestResult.ResponseData[0].WebAccount.UserName;
                    if (!szUserinfo.ToLower().Contains("microsoft.com"))
                    {
                        await Utils.ShowPopUp("Not a valid user. App now exits");
                        Windows.UI.Xaml.Application.Current.Exit();
                    }
                    if (!string.IsNullOrEmpty(szUserinfo) && szUserinfo.Contains("@"))  //TODO: This is not always alias, for some users emailid and alias is differnt
                        App.szUserAlias = szUserinfo.Split('@').First();

                    App.szUserName = App.szUserAlias;
                    
                }