MAUI .NET Set Window Size

user_2350981 0
Viewed 3804

How can I set the window size in MAUI?

Background info: I only care about Windows for this application - I chose MAUI so I could use Blazor for a desktop application. For some reason the default window size is massive (takes up almost all of my 1440p screen space). The application I'm making only needs about 600x600. Having a way to make the window size fixed would also be helpful although I'm happy to have the app simply be responsive.

maui-blazor maui-windows maui
3 Answers

Updated for Maui GA (I'll add to that discussion too):

#if WINDOWS
using Microsoft.UI;
using Microsoft.UI.Windowing;
using Windows.Graphics;
#endif

namespace YourAppNameHere;

public partial class App : Application
{
    const int WindowWidth = 400;
    const int WindowHeight = 300;
    public App()
    {
        InitializeComponent();

        Microsoft.Maui.Handlers.WindowHandler.Mapper.AppendToMapping(nameof(IWindow), (handler, view) =>
        {
#if WINDOWS
            var mauiWindow = handler.VirtualView;
            var nativeWindow = handler.PlatformView;
            nativeWindow.Activate();
            IntPtr windowHandle = WinRT.Interop.WindowNative.GetWindowHandle(nativeWindow);
            WindowId windowId = Microsoft.UI.Win32Interop.GetWindowIdFromWindow(windowHandle);
            AppWindow appWindow = Microsoft.UI.Windowing.AppWindow.GetFromWindowId(windowId);
            appWindow.Resize(new SizeInt32(WindowWidth, WindowHeight));
#endif
        });

        MainPage = new MainPage();
    }
    ...

OR if want to base it on requested dimensions of MainPage, before appending handler could do:

        MainPage = new MainPage();
        var width = (int)MainPage.WidthRequest;
        var height = (int)MainPage.HeightRequest;

then use those dimensions (probably add some padding to get whole window size, because MainPage is client area).

NOTE: I was testing for Windows, so in the drop-down at upper-left of source text editor pane, I had selected ... (net6.0-windows10.0.19041.0). That's why I did not notice that I needed #if around the usings, to avoid errors on Android etc.

user_1993640

This is How we did it :

https://github.com/BhangeeF16/MAUI-DOT-NET/blob/main/SampleApp/MauiProgram.cs

In MauiProgram.cs > CreateMauiApp

#if WINDOWS
        builder.ConfigureLifecycleEvents(events =>
        {
            events.AddWindows(wndLifeCycleBuilder =>
            {
                wndLifeCycleBuilder.OnWindowCreated(window =>
                {
                    IntPtr nativeWindowHandle = WinRT.Interop.WindowNative.GetWindowHandle(window);
                    WindowId win32WindowsId = Win32Interop.GetWindowIdFromWindow(nativeWindowHandle);
                    AppWindow winuiAppWindow = AppWindow.GetFromWindowId(win32WindowsId);    
                    if(winuiAppWindow.Presenter is OverlappedPresenter p)
                    { 
                       p.Maximize();
                       //p.IsAlwaysOnTop=true;
                       p.IsResizable=false;
                       p.IsMaximizable = false;
                       p.IsMinimizable=false;
                    }                     
                    else
                    {
                        const int width = 1920;
                        const int height = 1080;
                        winuiAppWindow.MoveAndResize(new RectInt32(1920 / 2 - width / 2, 1080 / 2 - height / 2, width, height));                      
                    }                        
                });
            });
        });
#endif
user_124175300

If you only want to do this for the Desktop Platforms, then you can do something similar to @ToolmakerSteve but per-platform by overriding the OnLaunched function within the Platforms/Windows/App.xaml.cs for example.

using Microsoft.UI;
using Microsoft.UI.Windowing;
using Windows.Graphics;
using WinRT.Interop;
//...
protected override void OnLaunched(LaunchActivatedEventArgs args)
{
    base.OnLaunched(args);

    var currentWindow = Application.Windows[0].Handler.PlatformView;
    IntPtr _windowHandle = WindowNative.GetWindowHandle(currentWindow);
    var windowId = Win32Interop.GetWindowIdFromWindow(_windowHandle);

    AppWindow appWindow = AppWindow.GetFromWindowId(windowId);
    appWindow.Resize(new SizeInt32(350, 600));
}

These methods of resizing are still not ideal as it will flicker when it's changing window size. This is simply because of the time taken between OnLaunch being fired and the window being resized by native win32 API calls. However, moving it directly to the Platform-specific code is a bit more semantic.

Unlike the other answer we cannot get the Requested dimensions from client pages to use as our Window dimensions.

user_131837820
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