MAUI获取主线程Dispatcher报错：调用时机异常，主窗口未创建

我尝试通过以下代码获取主线程的Dispatcher：

public partial class MainPage
{
    public MainPage()
    {
        InitializeComponent();
        
    }

    private async void OnButtonClicked(object sender, EventArgs e)
    {
        var disp = CoreApplication.MainView.CoreWindow.Dispatcher;
    }
}

执行后抛出如下错误：

Exception thrown: 'System.InvalidOperationException' in WinRT.Runtime.dll
WinRT information: Could not create a new view because the main window has not yet been created
An exception of type 'System.InvalidOperationException' occurred in WinRT.Runtime.dll but was not handled in user code
WinRT information: Could not create a new view because the main window has not yet been created
A method was called at an unexpected time.

问题原因 #

• 主窗口CoreWindow未完成初始化：虽然代码是在按钮点击事件中调用，但在部分WinUI/UWP场景下，CoreApplication.MainView对应的CoreWindow还未完全绑定到主线程的UI上下文，应用主窗口的初始化流程尚未完成就触发了该调用。
• 错误提示存在误导：错误信息里提到的"无法创建新视图因为主窗口尚未创建"并非实际问题，真实情况是你尝试访问的主窗口CoreWindow还未处于就绪状态，导致访问其Dispatcher时抛出异常。

内容的提问来源于stack exchange，提问作者yonutix