Toggling Focus Assist mode in Win 10 Programmatically

Question

There are a few unanswered questions to this pretty much everywhere I've looked so I suppose I should add mine to the tally.

I am looking to toggle Focus Assist mode in Win 10 programmatically and have thus far been unsuccessful with finding much documentation on this in both official and unofficial channels.

If I am not able to toggle focus assist programmatically, I will need to essentially emulate the same behavior meaning, that I will need to intercept and squelch incoming notifications until it is turned off and then display notifications that were silenced during this period.

It seems the only path available right now is to write some c++ using reversed WNF information and then pray it won't break in an update. Before I go down that rabbit hole I figured I'd see if anyone has done this or maybe can point me to a resource I haven't considered.

The notification listener is great and gives me access to said notifications to fulfills my secondary requirement but it does not allow me to silence them as they come in since it runs in parallel with vs interrupts the flow of the notification.

For folks that ask this question in the future, I've found these helpful:

• Notification listener: Access all notifications
• Is there a way to detect changes in Focus Assist (formerly Quiet Hours)
• Playing with the Windows Notification Facility (WNF)
• WNF IDs from perf_nt_c.dll (adk version 17692)

Answer 1

You can toggle the mode using WNF mechanism.

Generate binary content of the file "0" = 00 00 00 00 (hex) and file "1" = 02 00 00 00 (hex)

For example, in git bash

echo -n -e "\x00\x00\x00\x00" > 0
echo -n -e "\x02\x00\x00\x00" > 1

Clone repository: https://github.com/ionescu007/wnfun

pip install Pywin32
pip install hexdump

Turn on the Priority mode

python WnfDump.py -w WNF_SHEL_QUIET_MOMENT_SHELL_MODE_CHANGED 1

Turn off Focus Assist

python WnfDump.py -w WNF_SHEL_QUIET_MOMENT_SHELL_MODE_CHANGED 0

If you find a way to turn on the "Alarms only" mode, let me know.

You can use the same technique C++ as well.

EDIT: Actually, the command activates mode that is set for the "full screen mode" and the file content 01 00 00 00, would activate the "game mode". If both are turned off, the command will have no effect.

Answer 2

I am looking to toggle Focus Assist mode in Win 10 programmatically and have thus far been unsuccessful

Currently, UWP does not provide such api to switch Focus Assist mode programmatically . If you do want this feature, please feel free to ask for this feature on UserVoice.

Answer 3

Like Pavel Henrykhsen answer says, there is one programmatic, albeit undocumented and unsupported way of doing it. Here is an implementation, albeit written in Rust.

The relevant function is the ZwUpdateWnfStateData from the ntdll.dll. In this case, the relevant arguments are

1. The ID of the state, which I managed to find at https://github.com/googleprojectzero/sandbox-attacksurface-analysis-tools/blob/80d7fcc8df9c3160c814c60f5121ae46c560a1b5/NtApiDotNet/NtWnfWellKnownNames.cs#L865
2. A buffer with the values [0x02, 0x00, 0x00, 0x00]
3. The length of the buffer

All arguments after that can be safely ignored.

// Pseudo-code
ZwUpdateWnfStateData(
            0xd83063ea3bf5075UL,
            new byte[] {0x02, 0x00, 0x00, 0x00},
            4,
            0,
            0,
            0,
            0,
        );

This does seem to rely on the "when I'm using an app in full-screen" setting being turned on in the focus mode settings.

Also, if one attempts to use this to enable focus mode, I recommend first disabling focus mode (pass new byte[] {0x00, 0x00, 0x00, 0x00} instead). Then, after a few milliseconds, one can safely enable focus mode.