Fix intermediate pages not receiving query parameters in multi-page Shell navigation

src/Controls/src/Core/Shell/ShellNavigationManager.cs

@@ -221,14 +221,12 @@ public void HandleNavigated(ShellNavigatedEventArgs args)
 				_shell.PropertyChanged += WaitForWindowToSet;
 				var shellContent = _shell?.CurrentItem?.CurrentItem?.CurrentItem;
 
-				if (shellContent != null)
-					shellContent.ChildAdded += WaitForWindowToSet;
+				shellContent?.ChildAdded += WaitForWindowToSet;
 
 				_waitingForWindow = new ActionDisposable(() =>
 				{
 					_shell.PropertyChanged -= WaitForWindowToSet;
-					if (shellContent != null)
-						shellContent.ChildAdded -= WaitForWindowToSet;
+					shellContent?.ChildAdded -= WaitForWindowToSet;
 				});
 
 				void WaitForWindowToSet(object sender, EventArgs e)
@@ -320,7 +318,7 @@ public static void ApplyQueryAttributes(Element element, ShellRouteParameters qu
 				var mergedData = MergeData(element, filteredQuery, isPopping);
 
 				//if we are pop or navigating back, we need to apply the query attributes to the ShellContent
-				if (isPopping && mergedData.Count > 0 )
+				if (isPopping && mergedData.Count > 0)
 				{
 					element.SetValue(ShellContent.QueryAttributesProperty, mergedData);
 				}
@@ -341,6 +339,21 @@ public static void ApplyQueryAttributes(Element element, ShellRouteParameters qu
 					element.SetValue(ShellContent.QueryAttributesProperty, mergedData);
 				}
 			}
+			else if (element is Page)
+			{
+				// Intermediate page (not the last item, not wrapped in ShellContent).
+				// Apply prefix-filtered query parameters directly via the attached property,
+				// which triggers OnQueryAttributesPropertyChanged to handle IQueryAttributable,
+				// BindingContext propagation, and [QueryProperty] attributes.
+				if (filteredQuery.Count == 0 && !element.IsSet(ShellContent.QueryAttributesProperty))
+					return;
+
+				var mergedData = MergeData(element, filteredQuery, isPopping);
+				if (mergedData.Count > 0 || !isPopping)
+				{
+					element.SetValue(ShellContent.QueryAttributesProperty, mergedData);
+				}
+			}
 
 			ShellRouteParameters MergeData(Element shellElement, ShellRouteParameters data, bool isPopping)
 			{

src/Controls/tests/Core.UnitTests/ShellParameterPassingTests.cs

@@ -779,6 +779,208 @@ public async Task ShellSectionChangedSetsQueryAttributesProperty()
 				"QueryAttributesProperty should be set when changing ShellSection");
 		}
 
+		[Fact]
+		public async Task IntermediatePageReceivesPrefixedQueryParamsViaIQueryAttributable()
+		{
+			var shell = new TestShell();
+			var item = CreateShellItem(shellSectionRoute: "section", shellContentRoute: "content");
+			shell.Items.Add(item);
+
+			var intermediatePage = new ShellTestPage();
+			shell.RegisterPage("product", intermediatePage);
+			Routing.RegisterRoute("review", typeof(ShellTestPage));
+
+			await shell.GoToAsync("product/review?product.sku=seed-tomato&stars=5");
+
+			// Intermediate page should have received the prefixed param "sku"
+			Assert.Single(intermediatePage.AppliedQueryAttributes);
+			Assert.True(intermediatePage.AppliedQueryAttributes[0].ContainsKey("sku"));
+			Assert.Equal("seed-tomato", intermediatePage.AppliedQueryAttributes[0]["sku"]);
+
+			// Last page should have received "stars"
+			var lastPage = shell.CurrentPage as ShellTestPage;
+			Assert.NotNull(lastPage);
+			Assert.NotEqual(intermediatePage, lastPage);
+			Assert.Single(lastPage.AppliedQueryAttributes);
+			Assert.True(lastPage.AppliedQueryAttributes[0].ContainsKey("stars"));
+			Assert.Equal("5", lastPage.AppliedQueryAttributes[0]["stars"]);
+		}
+
+		[Fact]
+		public async Task IntermediatePageReceivesQueryPropertyAttributes()
+		{
+			var shell = new TestShell();
+			var item = CreateShellItem(shellSectionRoute: "section", shellContentRoute: "content");
+			shell.Items.Add(item);
+
+			var intermediatePage = new ShellTestPage();
+			shell.RegisterPage("product", intermediatePage);
+			Routing.RegisterRoute("review", typeof(ShellTestPage));
+
+			await shell.GoToAsync($"product/review?product.{nameof(ShellTestPage.SomeQueryParameter)}=hello");
+
+			Assert.Equal("hello", intermediatePage.SomeQueryParameter);
+		}
+
+		[Fact]
+		public async Task LastPageStillReceivesUnprefixedParamsWithIntermediatePages()
+		{
+			var shell = new TestShell();
+			var item = CreateShellItem(shellSectionRoute: "section", shellContentRoute: "content");
+			shell.Items.Add(item);
+
+			Routing.RegisterRoute("product", typeof(ShellTestPage));
+			Routing.RegisterRoute("review", typeof(ShellTestPage));
+
+			await shell.GoToAsync($"product/review?{nameof(ShellTestPage.SomeQueryParameter)}=world&stars=5");
+
+			// Last page (review) should get the unprefixed params
+			var lastPage = shell.CurrentPage as ShellTestPage;
+			Assert.NotNull(lastPage);
+			Assert.True(lastPage.AppliedQueryAttributes[0].ContainsKey(nameof(ShellTestPage.SomeQueryParameter)));
+			Assert.Equal("world", lastPage.AppliedQueryAttributes[0][nameof(ShellTestPage.SomeQueryParameter)]);
+			Assert.True(lastPage.AppliedQueryAttributes[0].ContainsKey("stars"));
+		}
+
+		[Fact]
+		public async Task MultipleIntermediatePagesEachReceiveOwnPrefixedParams()
+		{
+			var shell = new TestShell();
+			var item = CreateShellItem(shellSectionRoute: "section", shellContentRoute: "content");
+			shell.Items.Add(item);
+
+			var categoryPage = new ShellTestPage();
+			var productPage = new ShellTestPage();
+			shell.RegisterPage("category", categoryPage);
+			shell.RegisterPage("product", productPage);
+			Routing.RegisterRoute("review", typeof(ShellTestPage));
+
+			await shell.GoToAsync("category/product/review?category.name=seeds&product.sku=tomato&stars=5");
+
+			// First intermediate page gets category-prefixed params
+			Assert.Single(categoryPage.AppliedQueryAttributes);
+			Assert.True(categoryPage.AppliedQueryAttributes[0].ContainsKey("name"));
+			Assert.Equal("seeds", categoryPage.AppliedQueryAttributes[0]["name"]);
+
+			// Second intermediate page gets product-prefixed params
+			Assert.Single(productPage.AppliedQueryAttributes);
+			Assert.True(productPage.AppliedQueryAttributes[0].ContainsKey("sku"));
+			Assert.Equal("tomato", productPage.AppliedQueryAttributes[0]["sku"]);
+
+			// Last page gets unprefixed params
+			var lastPage = shell.CurrentPage as ShellTestPage;
+			Assert.NotNull(lastPage);
+			Assert.True(lastPage.AppliedQueryAttributes[0].ContainsKey("stars"));
+			Assert.Equal("5", lastPage.AppliedQueryAttributes[0]["stars"]);
+		}
+
+		[Fact]
+		public async Task OverlappingParamNamesDeliverCorrectValueToEachPage()
+		{
+			var shell = new TestShell();
+			var item = CreateShellItem(shellSectionRoute: "section", shellContentRoute: "content");
+			shell.Items.Add(item);
+
+			var intermediatePage = new ShellTestPage();
+			shell.RegisterPage("product", intermediatePage);
+			Routing.RegisterRoute("review", typeof(ShellTestPage));
+
+			// Both pages have "name" as key, but intermediate gets it via prefix
+			await shell.GoToAsync("product/review?product.name=IntermediateValue&name=DetailValue");
+
+			// Intermediate page should get "name=IntermediateValue"
+			Assert.Single(intermediatePage.AppliedQueryAttributes);
+			Assert.True(intermediatePage.AppliedQueryAttributes[0].ContainsKey("name"));
+			Assert.Equal("IntermediateValue", intermediatePage.AppliedQueryAttributes[0]["name"]);
+
+			// Last page should get "name=DetailValue", NOT "IntermediateValue"
+			var lastPage = shell.CurrentPage as ShellTestPage;
+			Assert.NotNull(lastPage);
+			Assert.NotEqual(intermediatePage, lastPage);
+			Assert.True(lastPage.AppliedQueryAttributes[0].ContainsKey("name"));
+			Assert.Equal("DetailValue", lastPage.AppliedQueryAttributes[0]["name"]);
+		}
+
+		[Fact]
+		public async Task IntermediatePageDoesNotReceiveUnprefixedParams()
+		{
+			var shell = new TestShell();
+			var item = CreateShellItem(shellSectionRoute: "section", shellContentRoute: "content");
+			shell.Items.Add(item);
+
+			var intermediatePage = new ShellTestPage();
+			shell.RegisterPage("product", intermediatePage);
+			Routing.RegisterRoute("review", typeof(ShellTestPage));
+
+			// "stars" is unprefixed — should only go to the last page
+			// "product.sku" is prefixed — should only go to intermediate
+			await shell.GoToAsync("product/review?product.sku=seed-tomato&stars=5&name=Alice");
+
+			// Intermediate page should only get "sku" (from "product.sku")
+			Assert.Single(intermediatePage.AppliedQueryAttributes);
+			Assert.True(intermediatePage.AppliedQueryAttributes[0].ContainsKey("sku"));
+			Assert.Equal("seed-tomato", intermediatePage.AppliedQueryAttributes[0]["sku"]);
+			// Should NOT contain unprefixed params
+			Assert.False(intermediatePage.AppliedQueryAttributes[0].ContainsKey("stars"));
+			Assert.False(intermediatePage.AppliedQueryAttributes[0].ContainsKey("name"));
+
+			// Last page should get both unprefixed params
+			var lastPage = shell.CurrentPage as ShellTestPage;
+			Assert.NotNull(lastPage);
+			Assert.True(lastPage.AppliedQueryAttributes[0].ContainsKey("stars"));
+			Assert.True(lastPage.AppliedQueryAttributes[0].ContainsKey("name"));
+			Assert.Equal("Alice", lastPage.AppliedQueryAttributes[0]["name"]);
+		}
+
+		[Fact]
+		public async Task IntermediatePageWithNoPrefixedParamsDoesNotReceiveEmptyQuery()
+		{
+			var shell = new TestShell();
+			var item = CreateShellItem(shellSectionRoute: "section", shellContentRoute: "content");
+			shell.Items.Add(item);
+
+			var intermediatePage = new ShellTestPage();
+			shell.RegisterPage("product", intermediatePage);
+			Routing.RegisterRoute("review", typeof(ShellTestPage));
+
+			// No prefixed params for "product" — only unprefixed params for last page
+			await shell.GoToAsync("product/review?name=Alice");
+
+			// Intermediate page should NOT receive ApplyQueryAttributes at all
+			Assert.Empty(intermediatePage.AppliedQueryAttributes);
+
+			// Last page should still get the param
+			var lastPage = shell.CurrentPage as ShellTestPage;
+			Assert.NotNull(lastPage);
+			Assert.Single(lastPage.AppliedQueryAttributes);
+			Assert.Equal("Alice", lastPage.AppliedQueryAttributes[0]["name"]);
+		}
+
+		[Fact]
+		public async Task IntermediatePageReceivesParamsOnReNavigation()
+		{
+			var shell = new TestShell();
+			var item = CreateShellItem(shellSectionRoute: "section", shellContentRoute: "content");
+			shell.Items.Add(item);
+
+			var intermediatePage = new ShellTestPage();
+			shell.RegisterPage("product", intermediatePage);
+			Routing.RegisterRoute("review", typeof(ShellTestPage));
+
+			// First navigation: push product + review
+			await shell.GoToAsync("product/review?product.sku=tomato&stars=5");
+			Assert.Single(intermediatePage.AppliedQueryAttributes);
+			Assert.Equal("tomato", intermediatePage.AppliedQueryAttributes[0]["sku"]);
+
+			// Navigate back to root
+			await shell.GoToAsync("//section/content");
+
+			// Second navigation with different params
+			await shell.GoToAsync("product/review?product.sku=pepper&stars=3");
+			Assert.Equal(2, intermediatePage.AppliedQueryAttributes.Count);
+			Assert.Equal("pepper", intermediatePage.AppliedQueryAttributes[1]["sku"]);
+		}
+
 		// ApplyQueryAttributes should NOT be called on an inactive (non-target) page's ViewModel
 		// when navigating back with query params on the second cycle through the same pages.
 		[Fact]