Added in generic ViewModel

src/core/Microsoft.PowerToys.Settings.UI/Activation/ActivationHandler.cs

@@ -0,0 +1,40 @@
+using System;
+using System.Threading.Tasks;
+
+namespace Microsoft.PowerToys.Settings.UI.Activation
+{
+    // For more information on understanding and extending activation flow see
+    // https://github.com/Microsoft/WindowsTemplateStudio/blob/master/docs/activation.md
+    internal abstract class ActivationHandler
+    {
+        public abstract bool CanHandle(object args);
+
+        public abstract Task HandleAsync(object args);
+    }
+
+    // Extend this class to implement new ActivationHandlers
+    internal abstract class ActivationHandler<T> : ActivationHandler
+        where T : class
+    {
+        // Override this method to add the activation logic in your activation handler
+        protected abstract Task HandleInternalAsync(T args);
+
+        public override async Task HandleAsync(object args)
+        {
+            await HandleInternalAsync(args as T);
+        }
+
+        public override bool CanHandle(object args)
+        {
+            // CanHandle checks the args is of type you have configured
+            return args is T && CanHandleInternal(args as T);
+        }
+
+        // You can override this method to add extra validation on activation args
+        // to determine if your ActivationHandler should handle this activation args
+        protected virtual bool CanHandleInternal(T args)
+        {
+            return true;
+        }
+    }
+}

src/core/Microsoft.PowerToys.Settings.UI/Activation/DefaultActivationHandler.cs

@@ -0,0 +1,39 @@
+using System;
+using System.Threading.Tasks;
+
+using Microsoft.PowerToys.Settings.UI.Services;
+
+using Windows.ApplicationModel.Activation;
+
+namespace Microsoft.PowerToys.Settings.UI.Activation
+{
+    internal class DefaultActivationHandler : ActivationHandler<IActivatedEventArgs>
+    {
+        private readonly Type _navElement;
+
+        public DefaultActivationHandler(Type navElement)
+        {
+            _navElement = navElement;
+        }
+
+        protected override async Task HandleInternalAsync(IActivatedEventArgs args)
+        {
+            // When the navigation stack isn't restored, navigate to the first page and configure
+            // the new page by passing required information in the navigation parameter
+            object arguments = null;
+            if (args is LaunchActivatedEventArgs launchArgs)
+            {
+                arguments = launchArgs.Arguments;
+            }
+
+            NavigationService.Navigate(_navElement, arguments);
+            await Task.CompletedTask;
+        }
+
+        protected override bool CanHandleInternal(IActivatedEventArgs args)
+        {
+            // None of the ActivationHandlers has handled the app activation
+            return NavigationService.Frame.Content == null && _navElement != null;
+        }
+    }
+}