Add minimum window sizes

WinUIGallery/App.xaml.cs

@@ -21,7 +21,10 @@
 using Windows.ApplicationModel.Activation;
 using WinUIGallery.DesktopWap.DataModel;
 using WASDK = Microsoft.WindowsAppSDK;
-
+using Microsoft.Windows.AppLifecycle;
+using System.IO;
+using WinUIGallery.Helper;
+
 namespace AppUIBasics
 {
     /// <summary>
@@ -30,23 +33,24 @@ namespace AppUIBasics
     sealed partial class App : Application
     {
         private static Window startupWindow;
+        private static Win32WindowHelper win32WindowHelper;
 
         public static string WinAppSdkDetails
         {
             // TODO: restore patch number and version tag when WinAppSDK supports them both
             get => string.Format("Windows App SDK {0}.{1}",
                 WASDK.Release.Major, WASDK.Release.Minor);
-        }
-
+        }
+
         public static string WinAppSdkRuntimeDetails
         {
             get
-            {
+            {
                 // Retrieve Windows App Runtime version info dynamically
-                var windowsAppRuntimeVersion =
-                    from module in Process.GetCurrentProcess().Modules.OfType<ProcessModule>()
-                    where module.FileName.EndsWith("Microsoft.WindowsAppRuntime.Insights.Resource.dll")
-                    select FileVersionInfo.GetVersionInfo(module.FileName);
+                var windowsAppRuntimeVersion =
+                    from module in Process.GetCurrentProcess().Modules.OfType<ProcessModule>()
+                    where module.FileName.EndsWith("Microsoft.WindowsAppRuntime.Insights.Resource.dll")
+                    select FileVersionInfo.GetVersionInfo(module.FileName);
                 return WinAppSdkDetails + ", Windows App Runtime " + windowsAppRuntimeVersion.First().FileVersion; 
             }
         }
@@ -107,6 +111,10 @@ protected override void OnLaunched(Microsoft.UI.Xaml.LaunchActivatedEventArgs ar
 
             startupWindow = WindowHelper.CreateWindow();
             startupWindow.ExtendsContentIntoTitleBar = true;
+
+            win32WindowHelper = new Win32WindowHelper(startupWindow);
+            win32WindowHelper.SetWindowMinMaxSize(new Win32WindowHelper.POINT() { x = 500, y = 500 });
+
 #if DEBUG
             if (System.Diagnostics.Debugger.IsAttached)
             {

WinUIGallery/Common/Win32.cs

@@ -17,12 +17,37 @@ internal static class Win32
         [DllImport("kernel32.dll", CharSet = CharSet.Auto)]
         public static extern IntPtr GetModuleHandle(IntPtr moduleName);
 
+        [DllImport("User32.dll")]
+        internal static extern int GetDpiForWindow(IntPtr hwnd);
+
+        [DllImport("user32.dll", EntryPoint = "SetWindowLong")]
+        internal static extern int SetWindowLong32(IntPtr hWnd, WindowLongIndexFlags nIndex, WinProc newProc);
+
+        [DllImport("user32.dll", EntryPoint = "SetWindowLongPtr")]
+        internal static extern IntPtr SetWindowLongPtr64(IntPtr hWnd, WindowLongIndexFlags nIndex, WinProc newProc);
+
+        [DllImport("user32.dll")]
+        internal static extern IntPtr CallWindowProc(IntPtr lpPrevWndFunc, IntPtr hWnd, WindowMessage Msg, IntPtr wParam, IntPtr lParam);
+
         public const int WM_ACTIVATE = 0x0006;
         public const int WA_ACTIVE = 0x01;
         public const int WA_INACTIVE = 0x00;
 
         public const int WM_SETICON = 0x0080;
         public const int ICON_SMALL = 0;
         public const int ICON_BIG = 1;
+
+        internal delegate IntPtr WinProc(IntPtr hWnd, WindowMessage Msg, IntPtr wParam, IntPtr lParam);
+
+        [Flags]
+        internal enum WindowLongIndexFlags : int
+        {
+            GWL_WNDPROC = -4,
+        }
+
+        internal enum WindowMessage : int
+        {
+            WM_GETMINMAXINFO = 0x0024,
+        }
     }
 }

WinUIGallery/ControlPages/TabViewPage.xaml.cs

@@ -245,12 +245,14 @@ private void TabCloseButtonOverlayModeComboBox_SelectionChanged(object sender, S
 
         private void TabViewWindowingButton_Click(object sender, Microsoft.UI.Xaml.RoutedEventArgs e)
         {
+            var tabViewSample = new TabViewWindowingSamplePage();
+
             var newWindow = WindowHelper.CreateWindow();
+            newWindow.ExtendsContentIntoTitleBar = true;
+            newWindow.Content = tabViewSample;
+            tabViewSample.LoadDemoData();
+            tabViewSample.SetupWindowMinSize(newWindow);
 
-            Frame frame = new Frame();
-            frame.RequestedTheme = ThemeHelper.RootTheme;
-            frame.Navigate(typeof(TabViewWindowingSamplePage), null);
-            newWindow.Content = frame;
             newWindow.Activate();
         }
     }

WinUIGallery/Helper/Win32WindowHelper.cs

@@ -0,0 +1,88 @@
+using System;
+using System.Runtime.InteropServices;
+using Microsoft.UI.Xaml;
+using static AppUIBasics.Win32;
+
+namespace WinUIGallery.Helper
+{
+    internal class Win32WindowHelper
+    {
+        private static WinProc newWndProc = null;
+        private static nint oldWndProc = nint.Zero;
+
+        private POINT? minWindowSize = null;
+        private POINT? maxWindowSize = null;
+
+        private readonly Window window;
+
+        public Win32WindowHelper(Window window)
+        {
+            this.window = window;
+        }
+
+        public void SetWindowMinMaxSize(POINT? minWindowSize = null, POINT? maxWindowSize = null)
+        {
+            this.minWindowSize = minWindowSize;
+            this.maxWindowSize = maxWindowSize;
+
+            var hwnd = GetWindowHandleForCurrentWindow(window);
+
+            newWndProc = new WinProc(WndProc);
+            oldWndProc = SetWindowLongPtr(hwnd, WindowLongIndexFlags.GWL_WNDPROC, newWndProc);
+        }
+
+        private static nint GetWindowHandleForCurrentWindow(object target) =>
+            WinRT.Interop.WindowNative.GetWindowHandle(target);
+
+        private nint WndProc(nint hWnd, WindowMessage Msg, nint wParam, nint lParam)
+        {
+            switch (Msg)
+            {
+                case WindowMessage.WM_GETMINMAXINFO:
+                    var dpi = GetDpiForWindow(hWnd);
+                    var scalingFactor = (float)dpi / 96;
+
+                    var minMaxInfo = Marshal.PtrToStructure<MINMAXINFO>(lParam);
+                    if (minWindowSize != null)
+                    {
+                        minMaxInfo.ptMinTrackSize.x = (int)(minWindowSize.Value.x * scalingFactor);
+                        minMaxInfo.ptMinTrackSize.y = (int)(minWindowSize.Value.y * scalingFactor);
+                    }
+                    if (maxWindowSize != null)
+                    {
+                        minMaxInfo.ptMaxTrackSize.x = (int)(maxWindowSize.Value.x * scalingFactor);
+                        minMaxInfo.ptMaxTrackSize.y = (int)(minWindowSize.Value.y * scalingFactor);
+                    }
+
+                    Marshal.StructureToPtr(minMaxInfo, lParam, true);
+                    break;
+
+            }
+            return CallWindowProc(oldWndProc, hWnd, Msg, wParam, lParam);
+        }
+
+        private nint SetWindowLongPtr(nint hWnd, WindowLongIndexFlags nIndex, WinProc newProc)
+        {
+            if (nint.Size == 8)
+                return SetWindowLongPtr64(hWnd, nIndex, newProc);
+            else
+                return new nint(SetWindowLong32(hWnd, nIndex, newProc));
+        }
+
+        internal struct POINT
+        {
+            public int x;
+            public int y;
+        }
+
+        [StructLayout(LayoutKind.Sequential)]
+        private struct MINMAXINFO
+        {
+            public POINT ptReserved;
+            public POINT ptMaxSize;
+            public POINT ptMaxPosition;
+            public POINT ptMinTrackSize;
+            public POINT ptMaxTrackSize;
+        }
+    }
+}

WinUIGallery/TabViewPages/TabViewWindowingSamplePage.xaml.cs

@@ -14,12 +14,14 @@
 using System.Threading.Tasks;
 using Windows.System;
 using DispatcherQueueHandler = Microsoft.UI.Dispatching.DispatcherQueueHandler;
+using WinUIGallery.Helper;
 
 namespace AppUIBasics.TabViewPages
 {
     public sealed partial class TabViewWindowingSamplePage : Page
     {
         private const string DataIdentifier = "MyTabItem";
+        private Win32WindowHelper win32WindowHelper;
         public TabViewWindowingSamplePage()
         {
             this.InitializeComponent();
@@ -29,6 +31,12 @@ public TabViewWindowingSamplePage()
             Loaded += TabViewWindowingSamplePage_Loaded;
         }
 
+        public void SetupWindowMinSize(Window window)
+        {
+            win32WindowHelper = new Win32WindowHelper(window);
+            win32WindowHelper.SetWindowMinMaxSize(new Win32WindowHelper.POINT() { x = 500, y = 300 });
+        }
+
         private void TabViewWindowingSamplePage_Loaded(object sender, RoutedEventArgs e)
         {
             var currentWindow = WindowHelper.GetWindowForElement(this);
@@ -57,16 +65,8 @@ private void Tabs_TabItemsChanged(TabView sender, Windows.Foundation.Collections
             }
         }
 
-        protected override void OnNavigatedTo(NavigationEventArgs e)
-        {
-            base.OnNavigatedTo(e);
-
-            SetupWindow();
-        }
-
-        void SetupWindow()
+        public void LoadDemoData()
         {
-
             // Main Window -- add some default items
             for (int i = 0; i < 3; i++)
             {
@@ -92,6 +92,7 @@ private void Tabs_TabDroppedOutside(TabView sender, TabViewTabDroppedOutsideEven
             var newWindow = WindowHelper.CreateWindow();
             newWindow.ExtendsContentIntoTitleBar = true;
             newWindow.Content = newPage;
+            newPage.SetupWindowMinSize(newWindow);
 
             newWindow.Activate();
         }