Win UI3开发笔记（六）设置软件最小尺寸

想设置最小尺寸为1000*100像素怎么做？

一、问gpt

csharp 复制代码

using Microsoft.UI.ViewManagement;
using Windows.UI.ViewManagement;

// 在应用程序启动时设置最小缩放尺寸
ApplicationView.PreferredLaunchViewSize = new Size { Width = 800, Height = 600 };
ApplicationView.PreferredLaunchWindowingMode = ApplicationViewWindowingMode.PreferredLaunchViewSize;

结果：没有效果。

csharp 复制代码

Application.Current.Window.SetPreferredMinSize(new Size(800, 600));

代码报错跑不了。

二、参考网站1

使用SetWindowSubclass函数钩住WM_GETMINMAXINFO并设置min大小，没有给出代码。

三、https://github.com/microsoft/microsoft-ui-xaml/issues/2945

问题：如何设置最小窗口大小（桌面）

给出的解决方案：

ApplicationView.GetForCurrentView().SetPreferredMinSize(new Size(800, 600));

直接跑不起来了，报错：System.Runtime.InteropServices.COMException:"找不到元素。 (0x80070490)"
Desktop WinUI 3在Window类上还没有MinSize或MaxSize属性，对于开发人员来说，这样做并不简单。在Win32中执行此操作的方法是侦听消息WM_GETMINMAXINFO，但您需要首先访问在Windows中获取消息的过程（WindowProc）。不幸的是，WinUI 3 Desktop没有公开它，所以解决方案是子类化。子类允许在WindowProc之前拦截和处理发送到窗口的消息。

但是PInvoke一直报错。

四、https://github.com/unoplatform/uno/discussions/9092

膜拜大佬，用最简单的方法解决问题

appwindow尺寸改变时，写在函数里，当尺寸小于最小的宽高时resize当前最小宽高。

原文代码：

csharp 复制代码

/// <summary>
/// Sets the size of the Application Window when running in Windows.
/// </summary>
/// <param name="window"></param>o
/// <param name="width"></param>
/// <param name="height"></param>
/// <returns></returns>
public static bool Resize(Window window, int width, int height)
{

    try
    {

#if NET7_0_WINDOWS10_0_18362
        // Use 'this' rather than 'window' as variable if this is about the current window.
        IntPtr hWnd = WinRT.Interop.WindowNative.GetWindowHandle(window);
        Microsoft.UI.WindowId windowId = Microsoft.UI.Win32Interop.GetWindowIdFromWindow(hWnd);
        AppWindow = Microsoft.UI.Windowing.AppWindow.GetFromWindowId(windowId);
        AppWindow.Resize(new Windows.Graphics.SizeInt32 { Width = width, Height = height });
        AppWindow.Changed += AppWindow_Changed;
#else
        _ = Log.Warn($"{nameof(WindowHelper)}.{nameof(Resize)}() is not currently supported on this platform.");

#endif

        return true;
    }
    catch (Exception ex)
    {
        _ = Log.Error(ex);
    }
    return false;
}

private static void AppWindow_Changed(Microsoft.UI.Windowing.AppWindow sender, Microsoft.UI.Windowing.AppWindowChangedEventArgs args)
{
    try
    {
#if NET7_0_WINDOWS10_0_18362
        if (AppWindow == null)
            return;

        if (AppWindow.Size.Height < MinHeight && AppWindow.Size.Width < MinWidth)
            AppWindow.Resize(new Windows.Graphics.SizeInt32 { Width = MinWidth, Height = MinHeight });
        else if (AppWindow.Size.Height < MinHeight)
            AppWindow.Resize(new Windows.Graphics.SizeInt32 { Width = AppWindow.Size.Width, Height = MinHeight });
        else if (AppWindow.Size.Width < MinWidth)
            AppWindow.Resize(new Windows.Graphics.SizeInt32 { Width = MinWidth, Height = AppWindow.Size.Height });
#endif

    }
    catch (Exception ex)
    {
        _ = Log.Error(ex);
    }
}