How to implement Synchronous for async operation(WebAuthenticationBroker::AuthenticateAsync)?

Question

Hi all,

I want implement a function to do WebAuthenticationBroker::AuthenticateAsync()
When the AuthenticateAsync complete, it will set a value(bLogin) to True.
And show "Login Success"

{
	LoginLiveServer();
	if(bLogin)
		OutputDebugString(L"Login Success ");
	else
		OutputDebugString(L"Login Fail ");
}
void CloudMediaMgr::LoginLiveServer()
{
	auto LoginOp = WebAuthenticationBroker::AuthenticateAsync(WebAuthenticationOptions::None, 
			ref new Uri(ref new String(_oauthUri.c_str())), _callbackUri);
	LoginOp->Completed = ref new AsyncOperationCompletedHandler<WebAuthenticationResult^>([this](
	IAsyncOperation<WebAuthenticationResult^>^ a, AsyncStatus b)
	{
		WebAuthenticationResult^ result = a->GetResults();
		if (result->ResponseStatus == WebAuthenticationStatus::Success)
        	{
			bLogin = true;
			// do something
		}
	});
}

But the actual result is show "Login Fail"
I also try using task object like this

task<WebAuthenticationResult^> webAuthTask(WebAuthenticationBroker::AuthenticateAsync(WebAuthenticationOptions::None, 
					ref new Uri(ref new String(_oauthUri.c_str())), _callbackUri));
webAuthTask.then([this](task<WebAuthenticationResult^> webAuthTask)
{
    WebAuthenticationResult^ result = webAuthTask.get();
    if (result->ResponseStatus == WebAuthenticationStatus::Success)
    {
	bLogin = true;
    }
});

But the actual result is show "Login Fail", too
How to implement synchronous for this situation?

Thanks

Answer 1

 

Hello,

 

I was not clear your point, If you get the login fail, you can throw a error to stop the async function. You can follow this document to handle error in lambda function.

http://msdn.microsoft.com/en-us/library/windows/apps/dd997692(v=vs.110).aspx

 

Also, you can cancellation the lambda function to meet the error.

Please take a look Error Handling and Cancellation section in

http://msdn.microsoft.com/en-us/magazine/hh781020.aspx

 

Best regards,

Jesse

---

Jesse Jiang [MSFT]
MSDN Community Support | Feedback to us

Answer 2

Hi Jesse,

Sorry, my English is bad.
My problem is "How to implement Synchronous for async operation"

For my sample code, the LoginLiveServer() just call the WebAuthenticationBroker::AuthenticateAsync()
We assumption the WebAuthenticationBroker::AuthenticateAsync() that it always success login

Following this sample code.

bLogin = false;
LoginLiveServer();
if(bLogin)
	OutputDebugString(L"Login Success ");
else
	OutputDebugString(L"Login Fail ");

Because the  WebAuthenticationBroker::AuthenticateAsync() is async operation
The task::then method returns immediately, and its delegate doesn't run until the AuthenticateAsync() work completes successfully

So, When the LoginLiveServer() have call.
The "bLogin" value is false. It doesn't change to true. It will show Text "Login Fail"
But after 5~10 sec, the WebAuthenticationBroker::AuthenticateAsync() it's complete.

I just want know how to block the LoginLiveServer() function before the WebAuthenticationBroker::AuthenticateAsync() complete

Thanks

Answer 3

Are you calling this on a UI thread or on a worker thread?

If you are calling it on a worker thread then you can call task::wait to wait for the task to finish.

If you are on the UI thread then making the task synchronous may hang the UI: your users will be much happier if you don't do this. Instead of blocking waiting for the task to finish put the tasks which depend on the login in your completion function.

--Rob