WinUI3 : application lifecycle events in desktop app

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WinUI3 : application lifecycle events in desktop app

Harshithraj1871 1,681

Hi,

I was trying go get different application events like, App minimized, maximized, when app goes to background and comes to foreground for winui3 desktop app.

I tried searching for this events, but I was only able to find app launched and window closed but I was not able to find proper documentation other than this.

It would be of great help if you cloud help me by pointing to the right documentation.

thank you

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Castorix31 88,051

Some events have been added like microsoft.ui.windowing.appwindowchangedeventargs,
otherwise WinUI 3 apps receive same messages as normal Win32 desktop apps, like WM_SYSCOMMAND and others, that can be intercepted with SetWindowSubclass)

Harshithraj1871 1,681 Reputation points

2022-12-22T08:59:17.283+00:00

Thank you I was able to catch minimized and maximized with WM_SYSCOMMAND, but i was not able to catch any event when i attached Changed event to app window. Only once AppWindow.Changed event got triggered when the window came up. then i was not able to trigger that event even with minimize maximize, close etc.
Castorix31 88,051 Reputation points

2022-12-22T10:04:25.147+00:00
I quickly tested in C# (too much time to compile in C++ on my PC) by adding in the event :

Console.Beep(6000, 10);

and the beep is generated when I minimize, maximize, resize, etc...

(Windows App SDK 1.1.0, Windows 10 21H1)
Harshithraj1871 1,681 Reputation points

2022-12-22T11:28:44.063+00:00

I did something like this

Did i miss anything here?
Castorix31 88,051 Reputation points

2022-12-22T19:19:52.06+00:00
The first parameter is AppWindow
I could do a test in C++ (it took me several hours to compile a few lines of code...)
and it also works like in C# :

void AppWindowChanged(Microsoft::UI::Windowing::AppWindow const& p0, Microsoft::UI::Windowing::AppWindowChangedEventArgs const& p1) { Beep(6000, 10); }
Harshithraj1871 1,681 Reputation points

2022-12-23T09:38:47.947+00:00

Oh okay, thank you

I tried using AppWindow, still it was the same behaviour

Castorix31 88,051

If I add random tests, it works in all cases :

    void AppWindowChanged(Microsoft::UI::Windowing::AppWindow const& p0, Microsoft::UI::Windowing::AppWindowChangedEventArgs const& p1)  
    {  
        //Beep(6000, 10);  
        p0.Title(L"");  
        if (p1.DidSizeChange())  
        {  
            p0.Title(L"Size");  
        }  
        if (p1.DidPositionChange())  
        {  
            p0.Title(L"Position");  
        }  
    }

Harshithraj1871 1,681 Reputation points

2022-12-28T10:10:58.727+00:00

Got the issue, this was because i had attached WindProc for this window with SetWindowSubclass and i think this event might have been ignored when it was fired. when i removed the SetWindowSubclass it worked fine.

So now the question is "Is Attaching a WindProc with SetWindowSubclass to a WinUI3 window is a right thing to do?"
Castorix31 88,051 Reputation points

2022-12-28T10:28:40.297+00:00

If you need to handle some particular messages which are not handled by default and
if you return correctly DefSubclassProc, SetWindowSubclass works fine.
Harshithraj1871 1,681 Reputation points

2022-12-28T10:36:33.207+00:00

When u said DefSubclassProc that is DefWindowProc right?
i handled it coreclty, this is my windowproc

Even with this simple WindowProc it doesnt work
Castorix31 88,051 Reputation points

2022-12-29T16:01:20.057+00:00

When u said DefSubclassProc that is DefWindowProc right?

No, DefSubclassProc function
(and SUBCLASSPROC callback has 6 parameters)
XUWANBIN 201 Reputation points

2022-12-29T16:20:36.153+00:00

My question, help me answer, thank you
Harshithraj1871 1,681 Reputation points

2022-12-30T06:23:51.713+00:00

thank you this was helpful

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WinUI3 : application lifecycle events in desktop app

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