Make HelpPage WebViews load on demand, and be destroyed when hidden

Author: marticliment

src/UniGetUI/Pages/HelpPage.xaml

@@ -95,9 +95,10 @@
         <Border
             Grid.Row="1"
             Grid.Column="0"
+            x:Name="WebViewBorder"
             Background="{ThemeResource ApplicationPageBackgroundThemeBrush}"
             CornerRadius="6">
-            <controls:WebView2 Name="WebView" Source="https://www.google.com/" />
+            <!--controls:WebView2 Name="WebView" Source="https://www.google.com/" /-->
         </Border>
         <ProgressBar
             Name="ProgressBar"

src/UniGetUI/Pages/HelpPage.xaml.cs

@@ -1,6 +1,7 @@
 using System.Diagnostics;
 using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Controls;
+using UniGetUI.Interface.Pages;
 
 // To learn more about WinUI, the WinUI project structure,
 // and more about our project templates, see: http://aka.ms/winui-project-info.
@@ -10,80 +11,110 @@ namespace UniGetUI.Interface.Dialogs
     /// <summary>
     /// An empty page that can be used on its own or navigated to within a Frame.
     /// </summary>
-    public sealed partial class HelpPage : Page
+    public sealed partial class HelpPage : Page, IDisposable, IEnterLeaveListener
     {
         private bool Initialized;
+        private WebView2? webView;
+        private Uri? lastUri;
+
         public HelpPage()
         {
             InitializeComponent();
             _ = InitializeWebView();
+        }
 
-            WebView.NavigationStarting += (_, e) =>
+        private async Task InitializeWebView()
+        {
+            webView = new();
+            WebViewBorder.Child = webView;
+            webView.NavigationStarting += (_, e) =>
             {
                 ProgressBar.Visibility = Visibility.Visible;
+                lastUri = new Uri(e.Uri);
                 if (e.Uri.ToString().Contains("marticliment.com") && !e.Uri.ToString().Contains("isWingetUIIframe"))
                 {
                     e.Cancel = true;
                     if (e.Uri.ToString().Contains('?'))
                     {
-                        WebView.Source = new Uri(e.Uri.ToString() + "&isWingetUIIframe");
+                        webView.Source = new Uri(e.Uri.ToString() + "&isWingetUIIframe");
                     }
                     else
                     {
-                        WebView.Source = new Uri(e.Uri.ToString() + "?isWingetUIIframe");
+                        webView.Source = new Uri(e.Uri.ToString() + "?isWingetUIIframe");
                     }
                 }
             };
-            WebView.NavigationCompleted += (_, _) => { ProgressBar.Visibility = Visibility.Collapsed; };
-        }
+            webView.NavigationCompleted += (_, _) =>
+            {
+                ProgressBar.Visibility = Visibility.Collapsed;
+            };
 
-        private async Task InitializeWebView()
-        {
-            await WebView.EnsureCoreWebView2Async();
+            await webView.EnsureCoreWebView2Async();
             Initialized = true;
-            WebView.Source = new Uri("https://marticliment.com/unigetui/help");
+            webView.Source = lastUri ?? new Uri("https://marticliment.com/unigetui/help");
         }
 
         private void BackButton_Click(object sender, RoutedEventArgs e)
         {
-            if (Initialized && WebView.CanGoBack)
+            if (Initialized && webView is not null && webView.CanGoBack)
             {
-                WebView.GoBack();
+                webView.GoBack();
             }
         }
 
         private void RightButton_Click(object sender, RoutedEventArgs e)
         {
 
-            if (Initialized && WebView.CanGoForward)
+            if (Initialized && webView is not null &&  webView.CanGoForward)
             {
-                WebView.GoForward();
+                webView.GoForward();
             }
         }
 
         private void HomeButton_Click(object sender, RoutedEventArgs e)
         {
 
-            if (Initialized)
+            if (Initialized && webView is not null)
             {
-                WebView.Source = new Uri("https://marticliment.com/unigetui/help");
+                webView.Source = new Uri("https://marticliment.com/unigetui/help");
             }
         }
 
         private void ReloadButton_Click(object sender, RoutedEventArgs e)
         {
-            if (Initialized)
+            if (Initialized && webView is not null)
             {
-                WebView.Reload();
+                webView.Reload();
             }
         }
 
         private void BrowserButton_Click(object sender, RoutedEventArgs e)
         {
-            if (Initialized)
+            if (Initialized && webView is not null)
             {
-                Process.Start(new ProcessStartInfo { FileName = WebView.Source.ToString().Replace("?isWingetUIIframe", "").Replace("&isWingetUIIframe", ""), UseShellExecute = true });
+                Process.Start(new ProcessStartInfo { FileName = webView.Source.ToString().Replace("?isWingetUIIframe", "").Replace("&isWingetUIIframe", ""), UseShellExecute = true });
             }
         }
+
+        public void Dispose()
+        {
+            webView?.Close();
+            WebViewBorder.Child = new UserControl();
+            webView = null;
+            Initialized = false;
+        }
+
+        public void OnEnter()
+        {
+            if (webView is null) _ = InitializeWebView();
+        }
+
+        public void OnLeave()
+        {
+            webView?.Close();
+            WebViewBorder.Child = new UserControl();
+            webView = null;
+            Initialized = false;
+        }
     }
 }