[Settings]Show No network error when trying to update (#21500)

src/settings-ui/Settings.UI/Strings/en-us/Resources.resw

@@ -1744,6 +1744,9 @@ From there, simply click on one of the supported files in the File Explorer and
   <data name="General_UpToDate.Title" xml:space="preserve">
     <value>PowerToys is up to date</value>
   </data>
+  <data name="General_CantCheck.Title" xml:space="preserve">
+    <value>Network error. Please try again later</value>
+  </data>
   <data name="General_DownloadAndInstall.Content" xml:space="preserve">
     <value>Download &amp; install</value>
   </data>

src/settings-ui/Settings.UI/ViewModels/GeneralViewModel.cs

@@ -7,6 +7,7 @@ using System.Diagnostics;
 using System.Globalization;
 using System.IO;
 using System.IO.Abstractions;
+using System.Net.NetworkInformation;
 using System.Reflection;
 using System.Runtime.CompilerServices;
 using System.Text.Json;
@@ -159,6 +160,7 @@ namespace Microsoft.PowerToys.Settings.UI.ViewModels
 
         private bool _isNewVersionDownloading;
         private bool _isNewVersionChecked;
+        private bool _isNoNetwork;
 
         private bool _settingsBackupRestoreMessageVisible;
         private string _settingsBackupMessage;
@@ -592,6 +594,14 @@ namespace Microsoft.PowerToys.Settings.UI.ViewModels
             }
         }
 
+        public bool IsNoNetwork
+        {
+            get
+            {
+                return _isNoNetwork;
+            }
+        }
+
         public bool SettingsBackupRestoreMessageVisible
         {
             get
@@ -737,6 +747,23 @@ namespace Microsoft.PowerToys.Settings.UI.ViewModels
         // callback function to launch the URL to check for updates.
         private void CheckForUpdatesClick()
         {
+            // check if network is available
+            bool isNetAvailable = IsNetworkAvailable();
+
+            // check if the state changed
+            bool prevState = _isNoNetwork;
+            _isNoNetwork = !isNetAvailable;
+            if (prevState != _isNoNetwork)
+            {
+                NotifyPropertyChanged(nameof(IsNoNetwork));
+            }
+
+            if (!isNetAvailable)
+            {
+                _isNewVersionDownloading = false;
+                return;
+            }
+
             RefreshUpdatingState();
             IsNewVersionDownloading = string.IsNullOrEmpty(UpdatingSettingsConfig.DownloadedInstallerFilename);
             NotifyPropertyChanged(nameof(IsDownloadAllowed));
@@ -886,5 +913,48 @@ namespace Microsoft.PowerToys.Settings.UI.ViewModels
                 NotifyPropertyChanged(nameof(IsDownloadAllowed));
             }
         }
+
+        /// <summary>
+        /// Indicates whether any network connection is available
+        /// Filter virtual network cards.
+        /// </summary>
+        /// <returns>
+        ///     <c>true</c> if a network connection is available; otherwise, <c>false</c>.
+        /// </returns>
+        public static bool IsNetworkAvailable()
+        {
+            if (!NetworkInterface.GetIsNetworkAvailable())
+            {
+                return false;
+            }
+
+            foreach (NetworkInterface ni in NetworkInterface.GetAllNetworkInterfaces())
+            {
+                // discard because of standard reasons
+                if ((ni.OperationalStatus != OperationalStatus.Up) ||
+                    (ni.NetworkInterfaceType == NetworkInterfaceType.Loopback) ||
+                    (ni.NetworkInterfaceType == NetworkInterfaceType.Tunnel))
+                {
+                    continue;
+                }
+
+                // discard virtual cards (virtual box, virtual pc, etc.)
+                if (ni.Description.Contains("virtual", StringComparison.OrdinalIgnoreCase) ||
+                    ni.Name.Contains("virtual", StringComparison.OrdinalIgnoreCase))
+                {
+                    continue;
+                }
+
+                // discard "Microsoft Loopback Adapter", it will not show as NetworkInterfaceType.Loopback but as Ethernet Card.
+                if (ni.Description.Equals("Microsoft Loopback Adapter", StringComparison.OrdinalIgnoreCase))
+                {
+                    continue;
+                }
+
+                return true;
+            }
+
+            return false;
+        }
     }
 }

src/settings-ui/Settings.UI/Views/GeneralPage.xaml

@@ -64,6 +64,13 @@
                                   IsTabStop="{Binding IsNewVersionCheckedAndUpToDate, Mode=OneWay}"
                                   IsOpen="{Binding IsNewVersionCheckedAndUpToDate, Mode=OneWay}"/>
 
+                    <!-- Network error while checking for new version -->
+                    <InfoBar x:Uid="General_CantCheck"
+                                  IsClosable="False"
+                                  Severity="Error"
+                                  IsTabStop="{Binding IsNoNetwork, Mode=OneWay}"
+                                  IsOpen="{Binding IsNoNetwork, Mode=OneWay}"/>
+
                     <!-- New version available -->
                     <InfoBar x:Uid="General_NewVersionAvailable"
                                   IsClosable="False"