Merge pull request #179 from MicrosoftEdge/user/pieths-ms/fix_wv2_uwp…

…_sample_app_warnings_and_child_process_destruction

Dispose of unnecessary WebView2 resources when navigating between pages in the WebView2 UWP sample app.

In the WebView2 UWP sample app, when navigating between pages, the garbage collector takes a long time to activate and does not remove WebView2 resources in a reasonable amount of time. This leaves behind all the render processes and other resources which can bog down low memory systems. This PR "closes" all WebView controls which are on a page that is being unloaded and thus releases all significant resources which are used by those controls.

SampleApps/webview2_sample_uwp/Package.appxmanifest

@@ -50,7 +50,6 @@
  <Capability Name="privateNetworkClientServer" />
  <uap:Capability Name="enterpriseAuthentication"/>
  <uap:Capability Name="sharedUserCertificates"/>
- <rescap:Capability Name="enterpriseCloudSSO" />
  <DeviceCapability Name="location"/>
  <DeviceCapability Name="microphone"/>
  <DeviceCapability Name="webcam"/> 

SampleApps/webview2_sample_uwp/Pages/AddHostObject.xaml

@@ -2,14 +2,14 @@
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.-->
 
-<Page
+<local:BasePage
  x:Class="WebView2_UWP.Pages.AddHostObject"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
- xmlns:local="using:WebView2_UWP.Pages"
  xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
  xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
  xmlns:controls="using:Microsoft.UI.Xaml.Controls"
+ xmlns:local="using:WebView2_UWP.Pages"
  mc:Ignorable="d"
  Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
 
@@ -77,5 +77,5 @@ found in the LICENSE file.-->
 
  <controls:WebView2 Grid.Column="1" x:Name="WebView2" />
  </Grid>
-</Page>
+</local:BasePage>
 

SampleApps/webview2_sample_uwp/Pages/AddHostObject.xaml.cs

@@ -11,7 +11,7 @@
 
 namespace WebView2_UWP.Pages
 {
- public sealed partial class AddHostObject : Page
+ public sealed partial class AddHostObject : BasePage
  {
  private Bridge _bridge;
 

SampleApps/webview2_sample_uwp/Pages/BasePage.cs

@@ -0,0 +1,43 @@
+// Copyright (C) Microsoft Corporation. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+using Microsoft.UI.Xaml.Controls;
+using System.Diagnostics;
+using Windows.UI.Xaml;
+using Windows.UI.Xaml.Controls;
+using Windows.UI.Xaml.Media;
+
+namespace WebView2_UWP.Pages
+{
+ public class BasePage : Page
+ {
+ public BasePage()
+ {
+ Unloaded += BasePage_Unloaded;
+ }
+
+ private void BasePage_Unloaded(object sender, RoutedEventArgs e)
+ {
+ // The garbage collector can be slow to dispose of the
+ // webviews. Manually free the resources being used by
+ // the webviews since they are no longer needed after
+ // the page has been unloaded.
+ CloseAllWebViews(this);
+ }
+
+ private void CloseAllWebViews(DependencyObject root)
+ {
+ for (int i = 0; i < VisualTreeHelper.GetChildrenCount(root); i++)
+ {
+ var childVisual = VisualTreeHelper.GetChild(root, i);
+ CloseAllWebViews(childVisual);
+
+ if (childVisual is WebView2 webView)
+ {
+ webView.Close();
+ }
+ }
+ }
+ }
+}

SampleApps/webview2_sample_uwp/Pages/Browser.xaml

@@ -2,13 +2,14 @@
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.-->
 
-<Page
+<local:BasePage
  x:Class="WebView2_UWP.Pages.Browser"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
  xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
  xmlns:controls="using:Microsoft.UI.Xaml.Controls"
+ xmlns:local="using:WebView2_UWP.Pages"
  mc:Ignorable="d"
  Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
 
@@ -45,4 +46,4 @@ found in the LICENSE file.-->
  <Rectangle Grid.Row="2" Fill="LightGray"/>
  <TextBlock x:Name="StatusBar" Text="WebView2" VerticalAlignment="Center" Grid.Row="2" Margin="10,0,10,0"/>
  </Grid>
-</Page>
+</local:BasePage>

SampleApps/webview2_sample_uwp/Pages/Browser.xaml.cs

@@ -19,13 +19,13 @@
 
 namespace WebView2_UWP.Pages
 {
- public sealed partial class Browser : Page
+ public sealed partial class Browser : BasePage
  {
  private string _homeUrl = "https://developer.microsoft.com/en-us/microsoft-edge/webview2/";
 
  public Browser()
  {
- this.InitializeComponent();
+ InitializeComponent();
  AddressBar.Text = _homeUrl;
 
  WebView2.CoreWebView2Initialized += WebView2_CoreWebView2Initialized;
@@ -36,7 +36,11 @@ public Browser()
  WebView2.Source = new Uri(AddressBar.Text);
  }
 
+#if USE_WEBVIEW2_SMOKETEST
  private async void WebView2_CoreWebView2Initialized(WebView2 sender, CoreWebView2InitializedEventArgs args)
+#else
+ private void WebView2_CoreWebView2Initialized(WebView2 sender, CoreWebView2InitializedEventArgs args)
+#endif
  {
  if (args.Exception != null)
  {
@@ -59,7 +63,7 @@ private async void WebView2_CoreWebView2Initialized(WebView2 sender, CoreWebView
  }
 
  // <DownloadStarting>
- private async void CoreWebView2_DownloadStarting(CoreWebView2 sender, CoreWebView2DownloadStartingEventArgs args)
+ private void CoreWebView2_DownloadStarting(CoreWebView2 sender, CoreWebView2DownloadStartingEventArgs args)
  {
  // Developer can obtain a deferral for the event so that the CoreWebView2
  // doesn't examine the properties we set on the event args until
@@ -142,13 +146,17 @@ private void StatusUpdate(string message)
  Debug.WriteLine(message);
  }
 
- private async void WebView2_NavigationStarting(WebView2 sender, CoreWebView2NavigationStartingEventArgs args)
+ private void WebView2_NavigationStarting(WebView2 sender, CoreWebView2NavigationStartingEventArgs args)
  {
  RefreshButton.IsEnabled = false;
  CancelButton.IsEnabled = true;
  }
 
+#if USE_WEBVIEW2_SMOKETEST
  private async void WebView2_NavigationCompleted(WebView2 sender, CoreWebView2NavigationCompletedEventArgs args)
+#else
+ private void WebView2_NavigationCompleted(WebView2 sender, CoreWebView2NavigationCompletedEventArgs args)
+#endif
  {
  StatusUpdate("Navigation complete");
 

SampleApps/webview2_sample_uwp/Pages/ExecuteJavascript.xaml

@@ -2,14 +2,14 @@
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.-->
 
-<Page
+<local:BasePage
  x:Class="WebView2_UWP.Pages.ExecuteJavascript"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
- xmlns:local="using:WebView2_UWP"
  xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
  xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
  xmlns:controls="using:Microsoft.UI.Xaml.Controls"
+ xmlns:local="using:WebView2_UWP.Pages"
  mc:Ignorable="d"
  Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
 
@@ -83,5 +83,5 @@ found in the LICENSE file.-->
 
  <controls:WebView2 Grid.Column="1" x:Name="WebView2" />
  </Grid>
-</Page>
+</local:BasePage>
 

SampleApps/webview2_sample_uwp/Pages/ExecuteJavascript.xaml.cs

@@ -10,7 +10,7 @@
 
 namespace WebView2_UWP.Pages
 {
- public sealed partial class ExecuteJavascript : Page
+ public sealed partial class ExecuteJavascript : BasePage
  {
  Dictionary<string, string> codeSnippets = new Dictionary<string, string>()
  {
@@ -29,7 +29,7 @@ public ExecuteJavascript()
  WebView2.Source = new Uri("http://appassets.html.example/execute_javascript.html");
  }
 
- private async void WebView2_CoreWebView2Initialized(WebView2 sender, CoreWebView2InitializedEventArgs args)
+ private void WebView2_CoreWebView2Initialized(WebView2 sender, CoreWebView2InitializedEventArgs args)
  {
  sender.CoreWebView2.SetVirtualHostNameToFolderMapping("appassets.html.example", "html", CoreWebView2HostResourceAccessKind.Allow);
  }

SampleApps/webview2_sample_uwp/Pages/NewWindow.xaml

@@ -2,14 +2,14 @@
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.-->
 
-<Page
+<local:BasePage
  x:Class="WebView2_UWP.Pages.NewWindow"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
- xmlns:local="using:WebView2_UWP.Pages"
  xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
  xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
  xmlns:controls="using:Microsoft.UI.Xaml.Controls"
+ xmlns:local="using:WebView2_UWP.Pages"
  mc:Ignorable="d"
  Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
 
@@ -78,4 +78,4 @@ found in the LICENSE file.-->
  </Grid>
 
  </Grid>
-</Page>
+</local:BasePage>

SampleApps/webview2_sample_uwp/Pages/NewWindow.xaml.cs

@@ -10,7 +10,7 @@
 
 namespace WebView2_UWP.Pages
 {
- public sealed partial class NewWindow : Page
+ public sealed partial class NewWindow : BasePage
  {
  public enum OptionEnum
  {
@@ -65,7 +65,7 @@ public NewWindow()
  WebView2.Source = new Uri("http://appassets.html.example/new_window.html");
  }
 
- private async void WebView2_CoreWebView2Initialized(WebView2 sender, CoreWebView2InitializedEventArgs args)
+ private void WebView2_CoreWebView2Initialized(WebView2 sender, CoreWebView2InitializedEventArgs args)
  {
  sender.CoreWebView2.SetVirtualHostNameToFolderMapping("appassets.html.example", "html", CoreWebView2HostResourceAccessKind.Allow);
  sender.CoreWebView2.NewWindowRequested += CoreWebView2_NewWindowRequested;

SampleApps/webview2_sample_uwp/Pages/PopupsAndDialogs.xaml

@@ -2,14 +2,14 @@
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.-->
 
-<Page
+<local:BasePage
  x:Class="WebView2_UWP.Pages.PopupsAndDialogs"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
- xmlns:local="using:WebView2_UWP.Pages"
  xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
  xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
  xmlns:controls="using:Microsoft.UI.Xaml.Controls"
+ xmlns:local="using:WebView2_UWP.Pages"
  mc:Ignorable="d"
  Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
 
@@ -100,4 +100,4 @@ found in the LICENSE file.-->
 
  <controls:WebView2 Grid.Column="1" x:Name="WebView2" />
  </Grid>
-</Page>
+</local:BasePage>

SampleApps/webview2_sample_uwp/Pages/PopupsAndDialogs.xaml.cs

@@ -13,7 +13,7 @@
 
 namespace WebView2_UWP.Pages
 {
- public sealed partial class PopupsAndDialogs : Page
+ public sealed partial class PopupsAndDialogs : BasePage
  {
  public PopupsAndDialogs()
  {
@@ -23,7 +23,7 @@ public PopupsAndDialogs()
  WebView2.Source = new Uri("http://appassets.html.example/popups_and_dialogs.html");
  }
 
- private async void WebView2_CoreWebView2Initialized(WebView2 sender, CoreWebView2InitializedEventArgs args)
+ private void WebView2_CoreWebView2Initialized(WebView2 sender, CoreWebView2InitializedEventArgs args)
  {
  WebView2.CoreWebView2.SetVirtualHostNameToFolderMapping("appassets.html.example", "html", CoreWebView2HostResourceAccessKind.Allow);
  }

SampleApps/webview2_sample_uwp/Pages/ScriptDebugging.xaml

@@ -2,13 +2,14 @@
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.-->
 
-<Page
+<local:BasePage
  x:Class="WebView2_UWP.Pages.ScriptDebugging"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
  xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
  xmlns:controls="using:Microsoft.UI.Xaml.Controls"
+ xmlns:local="using:WebView2_UWP.Pages"
  mc:Ignorable="d"
  Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
 
@@ -46,7 +47,7 @@ found in the LICENSE file.-->
 
  <controls:WebView2 Grid.Column="1" x:Name="WebView2" />
  </Grid>
-</Page>
+</local:BasePage>
 
 
 

SampleApps/webview2_sample_uwp/Pages/ScriptDebugging.xaml.cs

@@ -9,24 +9,24 @@
 
 namespace WebView2_UWP.Pages
 {
- public sealed partial class ScriptDebugging : Page
+ public sealed partial class ScriptDebugging : BasePage
  {
  public ScriptDebugging()
  {
  this.InitializeComponent();
  WebView2.CoreWebView2Initialized += WebView2_CoreWebView2Initialized;
  }
 
- private async void WebView2_CoreWebView2Initialized(WebView2 sender, CoreWebView2InitializedEventArgs args)
+ private void WebView2_CoreWebView2Initialized(WebView2 sender, CoreWebView2InitializedEventArgs args)
  {
  sender.CoreWebView2.SetVirtualHostNameToFolderMapping("appassets.html.example", "html", CoreWebView2HostResourceAccessKind.Allow);
  }
 
- private async void OnJavaScriptLocalFileButtonClicked(object sender, Windows.UI.Xaml.RoutedEventArgs e)
+ private void OnJavaScriptLocalFileButtonClicked(object sender, Windows.UI.Xaml.RoutedEventArgs e)
  {
  WebView2.Source = new Uri("http://appassets.html.example/ScenarioJavaScriptDebugIndex.html");
  }
- private async void OnTypeScriptLocalFileButtonClicked(object sender, Windows.UI.Xaml.RoutedEventArgs e)
+ private void OnTypeScriptLocalFileButtonClicked(object sender, Windows.UI.Xaml.RoutedEventArgs e)
  {
  WebView2.Source = new Uri("http://appassets.html.example/ScenarioTypeScriptDebugIndex.html");
  }

SampleApps/webview2_sample_uwp/Pages/SettingsPage.xaml.cs

@@ -10,6 +10,7 @@
 using webview2_sample_uwp;
 using Windows.ApplicationModel.Core;
 using Windows.Storage;
+using Windows.UI.Core;
 using Windows.UI.Popups;
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Controls;
@@ -160,6 +161,14 @@ private async void InitializeAppDetailsItems()
  Value = sender.CoreWebView2.Environment.UserDataFolder
  });
  }
+
+ // The garbage collector can be slow to dispose of the
+ // webview. Manually free the resources being used by
+ // the webview since it is no longer needed.
+ var ignored = Dispatcher.RunAsync(CoreDispatcherPriority.Low, () =>
+ {
+ webview2.Close();
+ });
  };
  await webview2.EnsureCoreWebView2Async();
  }

SampleApps/webview2_sample_uwp/webview2_sample_uwp.csproj

@@ -124,6 +124,7 @@
  <Compile Include="Pages\AddHostObject.xaml.cs">
  <DependentUpon>AddHostObject.xaml</DependentUpon>
  </Compile>
+ <Compile Include="Pages\BasePage.cs" />
  <Compile Include="Pages\Browser.xaml.cs">
  <DependentUpon>Browser.xaml</DependentUpon>
  </Compile>