Add fix for NavViewItems in footer crashing (#2395)

* Add fix for NavViewItems in footer crashing * CR feedback
microsoft · May 6, 2020 · a34eaf2 · a34eaf2
1 parent 1785888
commit a34eaf2
Show file tree

Hide file tree

Showing 3 changed files with 30 additions and 4 deletions.
diff --git a/dev/NavigationView/NavigationViewItemPresenter.cpp b/dev/NavigationView/NavigationViewItemPresenter.cpp
@@ -38,14 +38,16 @@ void NavigationViewItemPresenter::OnApplyTemplate()
             m_expandCollapseChevron.set(expandCollapseChevron);
             m_expandCollapseChevronTappedToken = expandCollapseChevron.Tapped({ navigationViewItem, &NavigationViewItem::OnExpandCollapseChevronTapped });
         }
-
         navigationViewItem->UpdateVisualStateNoTransition();
 
 
         // We probably switched displaymode, so restore width now, otherwise the next time we will restore is when the CompactPaneLength changes
-        if (navigationViewItem->GetNavigationView().PaneDisplayMode() != winrt::NavigationViewPaneDisplayMode::Top)
+        if(auto&& navigationView = navigationViewItem->GetNavigationView())
         {
-            UpdateCompactPaneLength(m_compactPaneLengthValue, true);
+            if (navigationView.PaneDisplayMode() != winrt::NavigationViewPaneDisplayMode::Top)
+            {
+                UpdateCompactPaneLength(m_compactPaneLengthValue, true);
+            }
         }
     }
 

diff --git a/dev/NavigationView/NavigationView_ApiTests/NavigationViewTests.cs b/dev/NavigationView/NavigationView_ApiTests/NavigationViewTests.cs
@@ -1,4 +1,4 @@
-// Copyright (c) Microsoft Corporation. All rights reserved.
+// Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License. See LICENSE in the project root for license information.
 
 using MUXControlsTestApp.Utilities;
@@ -685,5 +685,26 @@ public void VerifySelectedItemIsNullWhenNoItemIsSelected()
                 Verify.AreEqual(null, navView.SelectedItem, "SelectedItem should have been [null] as no item is selected");
             });
         }
+
+        [TestMethod]
+        public void VerifyNavigationViewItemInFooterDoesNotCrash()
+        {
+            RunOnUIThread.Execute(() =>
+            {
+                var navView = new NavigationView();
+
+                Content = navView;
+
+                var navViewItem = new NavigationViewItem() { Content = "Footer item" };
+
+                navView.PaneFooter = navViewItem;
+
+                navView.Width = 1008; // forces the control into Expanded mode so that the menu renders
+                Content.UpdateLayout();
+
+                // If we don't get here, app has crashed. This verify is just making sure code got run
+                Verify.IsTrue(true);
+            });
+        }
     }
 }
diff --git a/dev/NavigationView/TestUI/NavigationViewCompactPaneLengthTestPage.xaml b/dev/NavigationView/TestUI/NavigationViewCompactPaneLengthTestPage.xaml
@@ -36,6 +36,9 @@
                 <AutoSuggestBox QueryIcon="Find" AutomationProperties.Name="PaneAutoSuggestBox"/>
             </muxc:NavigationView.AutoSuggestBox>
 
+            <muxc:NavigationView.PaneFooter>
+                <muxc:NavigationViewItem Content="Footer item"/>
+            </muxc:NavigationView.PaneFooter>
 
             <muxc:NavigationView.Content>
                 <StackPanel Padding="50" Orientation="Horizontal">