WinUI3 : How to close all the visible window at once

Question

Hi,

I'm working on a WinUI3 desktop application in C++. I'm building a multiwindow application. Is there a way to close all the window at once in WinUI3?

One way is to maintain the List of windows ourselves, is there any other way to solve this? just like how win32 gives us EnumWindowsProc?

[PS : I want to close all the window without closing the event loop, so I'm maintaining an invisible window to keep the event loop alive]

Answer 1

Hi friend, I hope you're having a nice day.

In WinUI 3 for a C++ desktop application, if you want to close all windows at once without terminating the event loop, you need to manage the list of windows yourself, as there is no built-in equivalent to Win32's EnumWindowsProc in WinUI 3. However, you can achieve this by maintaining a list of window references and closing them programmatically.

Here’s how you can approach this:

Step-by-Step Approach

1. Maintain a List of Window References:
   • Store references to all your windows in a list or vector when you create them.
2. Close All Windows:
   • Iterate through the list and close each window when needed.

Example Implementation

Below is an example to illustrate this approach:

1. Header File (App.h):

#pragma once
    #include "App.xaml.g.h"
    #include <vector>
    class App : public winrt::implementation::AppT<App>
    {
    public:
        App();
        void OnLaunched(winrt::Microsoft::UI::Xaml::LaunchActivatedEventArgs const&);
        void CloseAllWindows();
    private:
        std::vector<winrt::Microsoft::UI::Xaml::Window> m_windows;
        winrt::Microsoft::UI::Xaml::Window m_invisibleWindow;
    };

2. Source File (App.cpp):

    #include "pch.h"
    #include "App.h"
    #include "MainWindow.h"
    App::App()
    {
        InitializeComponent();
    }
    void App::OnLaunched(winrt::Microsoft::UI::Xaml::LaunchActivatedEventArgs const&)
    {
        m_invisibleWindow = winrt::Microsoft::UI::Xaml::Window();
        m_invisibleWindow.Title(L"Invisible Window");
        m_invisibleWindow.Visibility(winrt::Microsoft::UI::Xaml::Visibility::Collapsed);
        m_invisibleWindow.Activate();
        auto mainWindow = winrt::make<MainWindow>();
        m_windows.push_back(mainWindow);
        mainWindow.Activate();
    }
    void App::CloseAllWindows()
    {
        for (auto& window : m_windows)
        {
            window.Close();
        }
        m_windows.clear();
    }

3. Main Window (MainWindow.xaml.cpp):

#include "pch.h"
    #include "MainWindow.xaml.h"
    MainWindow::MainWindow()
    {
        InitializeComponent();
    }

Usage

When you need to close all windows, you can call the CloseAllWindows method from the App class.

Invisible Window

To keep the event loop running, the invisible window is created in the OnLaunched method. It is kept hidden by setting its visibility to Collapsed. This window will prevent the event loop from exiting when all other windows are closed.

I hope this helps you. Have a nice day!!