WinUI 3 1.0：Window 就绪事件

Question

I am trying to execute code when the window is ready.

Specifically, I am trying to make the window maximize. The issue is I cannot run this code synchronously after InitializeComponent because it is too soon (the window is not yet ready/ loaded/ shown, so setting the Presenter has no effect)

The issue is the Window.Loaded event doesn't seem to be exposed by WinUI 3 (version 1.0).

So here is my current hack. In the constructor (after InitializeComponent ), I hook into one of the only events exposed by WinUI 3, Activated

Activated += MainWindow_Activated_FirstTime;

The issue is, this fires any time the window is focused, pretty much. So the workaround is I just remove the event handler, inside the event handler

private void MainWindow_Activated_FirstTime(object sender, WindowActivatedEventArgs args)
{
    SetupWindow();
    Activated -= MainWindow_Activated_FirstTime;
}

( SetupWindow sets the window presenter)

Now, like I said, this works , but I think it's pretty hacky. I was wondering if there was a proper way to hook into the Loaded or maybe some equivalent event like Ready or Rendered . I really don't care what I hook into as long as it's better than this.

Answer 1

If you have set the Content property of the window to a FrameworkElement , such as for example a Panel of any kind, you could handle the Loaded event of this one.

You could also use the DispatcherQueue to enqueue some work with low priority to be done as soon as the dispatcher thread is ready:

public MainWindow()
{
    this.InitializeComponent();
    Microsoft.UI.Dispatching.DispatcherQueue.GetForCurrentThread().TryEnqueue(
        Microsoft.UI.Dispatching.DispatcherQueuePriority.Low,
        new Microsoft.UI.Dispatching.DispatcherQueueHandler(() =>
        {
            //...
        }));
}

Answer 2

As of Win App Sdk 1.1.3, the event is now exposed

<Window
    x:Class="WindowsAppSdkTouchUI.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:AppExample"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:muxc="using:Microsoft.UI.Xaml.Controls"
    mc:Ignorable="d"
    Closed="Window_Closed"
    Activated="Window_Activated"> 

</Window>