Background UWP App using Phoneline.Dial not working under Locked Screen

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Background UWP App using Phoneline.Dial not working under Locked Screen

Peace Man 1

I used PhoneCallManager to dial a phone number which works great if I use DisplayRequest.Active to keep the App TopMost and Screen Un-Locked.

But If I do not use DisplayRequest.Active to prevent Screen Lock then the phone call is not placed despite the fact the Background Task is executing the code.

Is there a way to Un-Lock Screen from Background. Is there any way to place a call from Background Task when Screen is Locked.

I am using Visual Studio 2017...

Thanks

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Answer 1

Richard Zhang-MSFT 6,936 Microsoft Employee Moderator

Hello,

Welcome to Microsoft Q&A.

According to the document content of PhoneLine.Dial:

The caller must be in the foreground.

This means that your app must be in the foreground when this method is called. The application is not in the foreground when the screen is locked, so this method will not work.

In addition, If the application is a lock screen application (such as an application customized for Kiosk mode), the application can request the user to unlock through the LockApplicationHost.RequestUnlock method.

Thanks.

Peace Man 1 Reputation point

2020-08-31T14:01:13.62+00:00
THANKS!

I created Blank UWP App in Visual Studio 2017

public MainPage() { this.InitializeComponent(); LockApplicationHost lockHost = LockApplicationHost.GetForCurrentView(); lockApplicationHost.RequestUnlock(); }

this gives lockHost as null...suggestions?

research yields many un-objective leads.
Richard Zhang-MSFT 6,936 Reputation points Microsoft Employee Moderator

2020-08-31T14:19:18.007+00:00

Hello, I'm sorry that I did not elaborate. LockApplicationHost is suitable for lock screen applications (such as applications customized for Kiosk mode). This application will take over some functions of the lock screen interface. For regular applications, there may not be corresponding permissions to obtain the lock screen interface. So for now, calling PhoneLine.Dial must be done in the foreground.
Peace Man 1 Reputation point

2020-08-31T17:15:49.327+00:00

"For regular applications, there may not be corresponding permissions to obtain the lock screen interface. "

The word "may not" give me hope. Did you mean to say "can not". If no, what should I look into?
Richard Zhang-MSFT 6,936 Reputation points Microsoft Employee Moderator

2020-09-01T06:59:45.09+00:00

Hello, If your application is not a lock screen application, you cannot obtain the LockApplicationHost object. This also means that for regular applications, the screen can only be manually unlocked by the user. In other words, there is currently no method for regular apps to make calls when the screen is locked

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Background UWP App using Phoneline.Dial not working under Locked Screen

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