private async void SignIn()
{
ShowProgressRing(true);
// First of all, try to get OAuth URL by using specified ServerUrl
try
{
await CRMHelper.DiscoveryAuthority();
}
catch (Exception ex)
{
// If failed, then simply go back to page without doing anything more.
ShowProgressRing(false);
return;
}
// Assing ServerUrl, ResourceName to CRMHelper._proxy
CRMHelper._proxy.ServiceUrl = CRMHelper.ResourceName = txtServerUrl.Text;
// Cache ServerUrl
await Util.SaveToLocal(txtServerUrl.Text, "serverUrl.dat");
// Register background task.
await Util.RegisterBackgroundTask("CRMtoGoBackgroundTasks.UpdateSystemUserTimeZone",
"UpdateSystemUserTimeZone",
new SystemTrigger(SystemTriggerType.TimeZoneChange, false),
new SystemCondition(SystemConditionType.InternetAvailable));
// Initialize CRMHelper
await CRMHelper.Initialize();
Frame.Navigate(typeof(Home));
// To prevent user from back to this page by pressing back button, remove this page history from Navigation history
Frame.BackStack.RemoveAt(Frame.BackStackDepth - 1);
}
/// <summary>
/// This method try to obtain AccessToken by using OAuth2 authentication agianst Microsoft Azure AD.
/// </summary>
static public async Task GetTokenSilent()
{
// Before create AuthenticationContext, check if Authority(OAuthUrl) is available.
if (String.IsNullOrEmpty(CRMHelper.OAuthUrl))
{
bool success = true;
try
{
await CRMHelper.DiscoveryAuthority();
}
catch (Exception ex)
{
// If failed to retireve OAuthUrl, then make success as false
success = false;
}
// If failed to retrieve OAuthUrl, chances are user mistype ServerUrl.
if (!success)
{
MessageDialog dialog = new MessageDialog("OAuth Url retrieve failed. Please check Service URL again.");
await dialog.ShowAsync();
return;
}
}
if (CRMHelper.SignOut)
{
if (authContext != null)
{
authContext.TokenCache.Clear();
}
CRMHelper.SignOut = false;
}
// Create AuthenticationContext by using OAuthUrl.
if (authContext == null)
{
authContext = await AuthenticationContext.CreateAsync(CRMHelper.OAuthUrl);
}
// Try to acquire token without prompting user first.
AuthenticationResult result = await authContext.AcquireTokenSilentAsync(CRMHelper.ResourceName, CRMHelper.ClientId);
// Check the result.
if (result != null && result.Status == AuthenticationStatus.Success)
{
// A token was successfully retrieved. Then store it.
StoreToken(result);
}
// If failed to obtain token without prompting, then prompt user for credentials
else
{
// Clear AccessToken
CRMHelper._proxy.AccessToken = "";
// In case credential was wrong, clear the token cache first.
authContext.TokenCache.Clear();
// Acquiring a token without user interaction was not possible.
// Trigger an authentication experience and specify that once a token has been obtained the StoreToken method should be called.
authContext.AcquireTokenAndContinue(CRMHelper.ResourceName, CRMHelper.ClientId, new Uri(CRMHelper.RedirectUri), StoreToken);
}
}