Customize Windows

Use AppWindow for top-level window behavior and title bar APIs for chrome customization.

Get AppWindow

using Microsoft.UI;
using Microsoft.UI.Windowing;
using WinRT.Interop;

var hwnd = WindowNative.GetWindowHandle(App.MainWindow);
var windowId = Win32Interop.GetWindowIdFromWindow(hwnd);
var appWindow = AppWindow.GetFromWindowId(windowId);

Resize Or Change Presenter

appWindow.Resize(new Windows.Graphics.SizeInt32(1200, 800));

if (AppWindowPresenter.Create(AppWindowPresenterKind.CompactOverlay) is AppWindowPresenter presenter)
{
    appWindow.SetPresenter(presenter);
}

Title Bar Discipline

• Use simple title bar property changes before full custom title bars.
• If extending content into the title bar, handle drag regions and interactive controls carefully.
• Test DPI scaling and hit testing.
• Recheck current TitleBar control guidance before implementing new Windows App SDK 1.7+ title bar features.