YourPhone.Calling.Managed Get a call line from a line ID.

The OS often rapidly adds, removes (and updates) PhoneLines. This is known to happen when switching between devices or when setting up a new device for HFP. Trying to call PhoneLine.FromIdAsync on a line ID that is invalid, or one that has now been removed by the OS, or when Bluetooth is off results in E_NOT_FOUND being thrown. (https://task.ms/56321970) trackes these spurious calls from the OS. Regardless, this is no longer an unknown exception.

The only way of detecting that a device was unpaired while PL was not running is through DeviceInformation APIs Disposes the current pairedDeviceWatcher if it exists. Should only be called under disposeLock. InitializeComponent() Connect() GetBindingConnector(int connectionId, object target) InitializeComponent() Connect() GetBindingConnector(int connectionId, object target) The Dependency property backing the ViewModel property InitializeComponent() Connect() GetBindingConnector(int connectionId, object target) The Dependency property backing the ViewModel property InitializeComponent() Connect() GetBindingConnector(int connectionId, object target) The Dependency property backing the ViewModel property Gets or sets the viewmodel the chrome binds to. The Dependency property backing the PadTitleBar property The Dependency property backing the VerticalContentShift property InitializeComponent() Connect() GetBindingConnector(int connectionId, object target) The Dependency property backing the SelectedContact property The Dependency property backing the SuggestionsProvider property The Dependency property backing the PlaceholderText property InitializeComponent() Connect() GetBindingConnector(int connectionId, object target) The Dependency property backing the DialedNumber property The Dependency property backing the CanCall property InitializeComponent() UnloadObject(DependencyObject) Connect() DisconnectUnloadedObject(int connectionId) GetBindingConnector(int connectionId, object target) The Dependency property backing the PrimaryContentStyle property The Dependency property backing the PrimaryContent property The Dependency property backing the SecondaryContent property The Dependency property backing the SecondaryContentStyle property The Dependency property backing the ButtonType property The Dependency property backing the SecondaryContentVisibility property The Dependency property backing the ShouldNarrateContent property InitializeComponent() Connect() GetBindingConnector(int connectionId, object target) There was a Windows bug in certain builds that prevents in-band ringing from working. Specifically Windows will not play the phone ringtone even when PhoneLineTransportDevice.InBandRingingEnabled returns true. In these cases, we need to force a custom ringtone so that users don't miss incoming calls. https://microsoft.visualstudio.com/OS/_workitems/edit/45126205 Classifies a call's start time into a and resolves the localized header text and timestamp format for each section. Classifies relative to by local calendar date. The start time is converted to local time, and only the date component is considered; the time of day and elapsed hours are ignored. As a result, a call late in the previous evening is classified as Yesterday even if fewer than 24 hours have elapsed, and a call earlier today is Today even if it is nearly 24 hours old. The "this week" and "last month" windows span a fixed number of whole calendar days back from today. Per-window view-model for a mini calling window. Owns the window's current content (a dial-confirmation prompt or an active call) so the windowing layer can drive the window through this view-model instead of reaching into the view. Assigned by the view to service per-window exit-confirmation prompts, letting the windowing layer request confirmation without holding a reference to the view. Promotes a dial-confirmation window to an active call. Sets the active call before clearing the dial-confirmation VM so the view transitions straight to the active state. Screen-reader description of the call target for the confirm-before-dial speedbump: the contact name, the number when shown separately, and the "Call using…" subtitle. The Call button references this via AutomationProperties.DescribedBy, so Narrator reads who is being called when the button takes focus. Reuses the values already shown on the card. Ends the call. When another call exists, HFP can't end a held call directly (the OS rejects it), so this resumes the held call first, waits for phone confirmation, then ends. A lone held call ends fine, so the resume is a no-op cost in that case. Because PhoneCallInfo.StartTime is more a guardrail than a reflection of what the phone shows, trying to attain sub-second accuracy with respect to that timestamp is meaningless. InitializeComponent() Connect() GetBindingConnector(int connectionId, object target) InitializeComponent() Connect() GetBindingConnector(int connectionId, object target) Whether ending this call is allowed right now. A held call can only be ended by resuming first (HFP can't end a held call directly), which can't happen while another call is dialing. The exit-confirmation dialog binds its End button to this, so the user can't confirm the close in that state. Re-evaluates live as IsHeld/IsDialing change, so it re-enables once the dial resolves. Whether the end-call confirmation should warn that ending this call will briefly interrupt another active call. The genuinely held call is always the secondary; when its window is closed it is resumed-then-ended, which briefly interrupts the active primary. Restricting to the secondary slot also avoids a false positive during that teardown, where the primary is momentarily auto-held while the ending secondary is still talking. Re-evaluates live as the slots / IsHeld / IsAnyCallTalking change. Moves initial focus to the confirm-before-dial primary action for the current state — the Call button when ready, or the Open Phone Link button on failure — instead of leaving focus on the title-bar minimize button. On window open Narrator reads the focused element, and each action is described by its adjacent card, so the user hears the call target or the failure reason. No-op in the connecting state, which has no actionable element. Deferred so focus runs after layout and visibility have settled. Per-window exit confirmation for mini UX. Shows the flyout and returns true if the user confirmed, false if cancelled. This avoids the shared ExitConfirmationRequested event which fires on all windows simultaneously. InitializeComponent() Connect() GetBindingConnector(int connectionId, object target) InitializeComponent() Connect() GetBindingConnector(int connectionId, object target) InitializeComponent() Connect() GetBindingConnector(int connectionId, object target) InitializeComponent() Connect() GetBindingConnector(int connectionId, object target) InitializeComponent() Connect() GetBindingConnector(int connectionId, object target) InitializeComponent() Connect() GetBindingConnector(int connectionId, object target) Main class for providing metadata for the app or library GetXamlType(Type) GetXamlType(String) GetXmlnsDefinitions() Contains extern methods from "KERNEL32.dll". Contains extern methods from "USER32.dll". A window receives this message when the user chooses a command from the Window menu (formerly known as the system or control menu) or when the user chooses the maximize button, minimize button, restore button, or close button. An application should return zero if it processes this message. To obtain the position coordinates in screen coordinates, use the following code: This doc was truncated. Read more on docs.microsoft.com. Closes an open object handle. A valid handle to an open object. If the function succeeds, the return value is nonzero. If the function fails, the return value is zero. To get extended error information, call GetLastError. If the application is running under a debugger, the function will throw an exception if it receives either a handle value that is not valid or a pseudo-handle value. This can happen if you close a handle twice, or if you call CloseHandle on a handle returned by the FindFirstFile function instead of calling the FindClose function. The CloseHandle function closes handles to the following objects: This doc was truncated. Read more on docs.microsoft.com. Places (posts) a message in the message queue associated with the thread that created the specified window and returns without waiting for the thread to process the message. (Unicode) Type: HWND A handle to the window whose window procedure is to receive the message. The following values have special meanings. This doc was truncated. Read more on docs.microsoft.com. Type: UINT The message to be posted. For lists of the system-provided messages, see System-Defined Messages. Read more on docs.microsoft.com. Type: WPARAM Additional message-specific information. Read more on docs.microsoft.com. Type: LPARAM Additional message-specific information. Read more on docs.microsoft.com. Type: BOOL If the function succeeds, the return value is nonzero. If the function fails, the return value is zero. To get extended error information, call GetLastError. When a message is blocked by UIPI the last error, retrieved with GetLastError, is set to 5 (access denied). Messages in a message queue are retrieved by calls to the GetMessage or PeekMessage function. Applications that need to communicate using HWND_BROADCAST should use the RegisterWindowMessage function to obtain a unique message for inter-application communication. The system only does marshalling for system messages (those in the range 0 to (WM_USER-1)). To send other messages (those >= WM_USER) to another process, you must do custom marshalling. If you send a message in the range below WM_USER to the asynchronous message functions (PostMessage, SendNotifyMessage, and SendMessageCallback), its message parameters cannot include pointers. Otherwise, the operation will fail. The functions will return before the receiving thread has had a chance to process the message and the sender will free the memory before it is used. Do not post the WM_QUIT message using PostMessage; use the PostQuitMessage function. An accessibility application can use PostMessage to post WM_APPCOMMAND messages to the shell to launch applications. This functionality is not guaranteed to work for other types of applications. There is a limit of 10,000 posted messages per message queue. This limit should be sufficiently large. If your application exceeds the limit, it should be redesigned to avoid consuming so many system resources. To adjust this limit, modify the following registry key. 
HKEY_LOCAL_MACHINE SOFTWARE Microsoft Windows NT CurrentVersion Windows USERPostMessageLimit
If the function fails, call GetLastError to get extended error information. GetLastError returns ERROR_NOT_ENOUGH_QUOTA when the limit is hit. The minimum acceptable value is 4000. Read more on docs.microsoft.com.