使用 Rust 的子窗口

我正在尝试使用标准 Windows API 窗口和子窗口作为控件（最具体的是静态文本、文本框和按钮）创建一个窗口窗体。

我正在使用 Windows 板条箱，代码编译时没有任何错误并运行，但我只能看到空白窗口，而看不到里面的控件。

我做错了什么？

提前致谢！

#![allow(non_snake_case)]

use windows::{
    core::*, 
    Win32::Foundation::*, 
    Win32::Graphics::Gdi::*,
    Win32::System::LibraryLoader::GetModuleHandleA, 
    Win32::UI::WindowsAndMessaging::*,
};


fn main() -> Result<()> {
    unsafe {
        let instance = GetModuleHandleA(None)?;
        let window_class = s!("window");

        let wc = WNDCLASSA {
            hCursor: LoadCursorW(None, IDC_ARROW)?,
            hInstance: instance.into(),
            lpszClassName: window_class,
            style: CS_HREDRAW | CS_VREDRAW,
            lpfnWndProc: Some(wndproc),
            ..Default::default()
        };

        let atom = RegisterClassA(&wc);
        debug_assert!(atom != 0);

        let _hwnd = CreateWindowExA(
            WINDOW_EX_STYLE::default(),
            window_class,
            s!("A simple Form"),
            WS_OVERLAPPEDWINDOW | WS_VISIBLE,
            CW_USEDEFAULT,
            CW_USEDEFAULT,
            CW_USEDEFAULT,
            CW_USEDEFAULT,
            None,
            None,
            instance,
            None,
        )?;

    let _hndLabel = CreateWindowExA(
               WINDOW_EX_STYLE::default(),
               s!("static"), 
               s!("What's your name? "),
               WINDOW_STYLE::default(),
                           50, 100, 200, 30, _hwnd, None, instance, None)?;

    let _hndCaixa = CreateWindowExA(
                WINDOW_EX_STYLE::default(),
                s!("edit"), 
                s!("Type Here!"),
                WINDOW_STYLE::default(),
                            200, 100, 200, 30, _hwnd, None, instance, None)?;

    let _hndButton = CreateWindowExA(
                WINDOW_EX_STYLE::default(),
                s!("Button"), 
                s!("  OK  "),
                WINDOW_STYLE::default(),
                            400, 100, 200, 30, _hwnd, None, instance, None)?;

        let _ = ShowWindow(_hwnd, SW_SHOW);
    let _ = UpdateWindow(_hwnd);

        let mut message = MSG::default();

        while GetMessageA(&mut message, None, 0, 0).into() {
            DispatchMessageA(&message);
        }

        Ok(())
    }
}

extern "system" fn wndproc(window: HWND, message: u32, wparam: WPARAM, lparam: LPARAM) -> LRESULT {
    unsafe {
        match message {
            WM_PAINT => {
                println!("WM_PAINT");
                _ = ValidateRect(window, None);

                LRESULT(0)
            }
            WM_DESTROY => {
                println!("WM_DESTROY");
                PostQuitMessage(0);
                LRESULT(0)
            }
            _ => DefWindowProcA(window, message, wparam, lparam),
        }
    }
}