Proposal: Please directly create the top-level ```Microsoft.UI.Xaml.Window``` in the Window class using ```Microsoft.UI.Windowing.AppWindow```

# Proposal: Proposal: Please directly create the top-level ```Microsoft.UI.Xaml.Window``` in the Window class using ```Microsoft.UI.Windowing.AppWindow```

请直接在 ```Microsoft.UI.Xaml.Window``` 类中使用 ```Microsoft.UI.Windowing.AppWindow``` 创建顶层窗口

## Summary

Currently WinUI 3 Window class to create a desktop application Window is custom WinUIDesktopWin32WindowClass Window + DesktopWindowXamlSource + AppWindow combining with the combination of the top-level Window. AppWindow can directly create top-level Windows. Therefore, it is hoped that in the future, this part can be combined and the top-level Windows created by AppWindow can be directly used as the top-level Windows of the Window class.

目前 WinUI 3 桌面应用中的 Window 类创建的窗口是自定义的 WinUIDesktopWin32WindowClass 窗口 + DesktopWindowXamlSource + AppWindow 结合该顶层窗口组合的。而 AppWindow 是可以直接创建顶层窗口的，所以希望未来能组合一下这一部分，直接使用 AppWindow 创建的顶层窗口作为 Window 类的顶层窗口。

## Rationale

* {First reason for why we should consider this proposal}
* {Second reason for why we should consider this proposal}
* {etc}

## Scope

| Capability | Priority |
| :---------- | :------- |
| This proposal will allow developers to accomplish W | Must |
| This proposal will allow end users to accomplish X | Should |
| This proposal will allow developers to accomplish Y | Could |
| This proposal will allow end users to accomplish Z | Won't |

## Important Notes

## Open Questions

Start with the linked WinUI feature/API proposal process and compare the current Window composition described here: WinUIDesktopWin32WindowClass, DesktopWindowXamlSource, and AppWindow. Clarify the proposed API and resolve the Scope, Rationale, and Open Questions sections; done means the proposal has a concrete, reviewable design rather than template placeholders.

Written by the indexing model from the issue text.