TreeView: Set IsExpanded when last child has been removed (#2449)

* Add test for IsExpanded not being set to false when removing last child * Fix issue with setting IsExpanded not to false when removing last child * Fix test failures * Fix test
microsoft · Jul 7, 2020 · 0a12fab · 0a12fab
1 parent 180f212
commit 0a12fab
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Showing 3 changed files with 74 additions and 6 deletions.
diff --git a/dev/TreeView/APITests/TreeViewTests.cs b/dev/TreeView/APITests/TreeViewTests.cs
@@ -667,6 +667,49 @@ public void TreeViewSelectionChangedMultipleMode()
             });
         }
 
+        [TestMethod]
+        public void RemovingLastChildrenSetsIsExpandedToFalse()
+        {
+            RunOnUIThread.Execute(() =>
+            {
+                var treeViewRoot = new TreeViewNode();
+                var treeViewNode1 = new TreeViewNode();
+                var treeViewNode2 = new TreeViewNode();
+                var treeViewNode3 = new TreeViewNode();
+                var treeViewNode4 = new TreeViewNode();
+                var treeViewNode5 = new TreeViewNode();
+
+                // Need root since in TreeView we otherwise 
+                // could collapse whole tree and hide it forever
+                treeViewRoot.Children.Add(treeViewNode1);
+
+                treeViewNode1.Children.Add(treeViewNode2);
+                treeViewNode1.Children.Add(treeViewNode3);
+                treeViewNode1.Children.Add(treeViewNode4);
+                treeViewNode1.Children.Add(treeViewNode5);
+
+                treeViewNode1.IsExpanded = true;
+                Verify.IsTrue(treeViewNode1.IsExpanded);
+
+                treeViewNode1.Children.Clear();
+                Verify.IsFalse(treeViewNode1.IsExpanded);
+
+                treeViewNode1.Children.Add(treeViewNode2);
+                treeViewNode1.IsExpanded = true;
+                Verify.IsTrue(treeViewNode1.IsExpanded);
+
+                treeViewNode1.Children.Remove(treeViewNode2);
+                Verify.IsFalse(treeViewNode1.IsExpanded);
+
+                treeViewNode1.Children.Add(treeViewNode2);
+                treeViewNode1.IsExpanded = true;
+                Verify.IsTrue(treeViewNode1.IsExpanded);
+
+                treeViewNode1.Children.RemoveAt(0);
+                Verify.IsFalse(treeViewNode1.IsExpanded);
+            });
+        }
+
         private bool IsMultiSelectCheckBoxChecked(TreeView tree, TreeViewNode node)
         {
             var treeViewItem = tree.ContainerFromNode(node) as TreeViewItem;

diff --git a/dev/TreeView/TreeViewNode.cpp b/dev/TreeView/TreeViewNode.cpp
@@ -231,7 +231,7 @@ void TreeViewNode::SyncChildrenNodesWithItemsSource()
     if (!AreChildrenNodesEqualToItemsSource())
     {
         auto children = winrt::get_self<TreeViewNodeVector>(Children());
-        children->Clear(false /* updateItemsSource */);
+        children->Clear(false /* updateItemsSource */, false /* updateIsExpanded */);
 
         auto size = m_itemsDataSource ? m_itemsDataSource.Count() : 0;
         for (auto i = 0; i < size; i++)
@@ -383,11 +383,11 @@ void TreeViewNodeVector::InsertAt(unsigned int index, winrt::TreeViewNode const&
 
 void TreeViewNodeVector::SetAt(unsigned int index, winrt::TreeViewNode const& item, bool updateItemsSource)
 {
-    RemoveAt(index, updateItemsSource);
+    RemoveAt(index, updateItemsSource,false /* updateIsExpanded */);
     InsertAt(index, item, updateItemsSource);
 }
 
-void TreeViewNodeVector::RemoveAt(unsigned int index, bool updateItemsSource)
+void TreeViewNodeVector::RemoveAt(unsigned int index, bool updateItemsSource,bool updateIsExpanded)
 {
     auto inner = GetVectorInnerImpl();
     auto targetNode = inner->GetAt(index);
@@ -402,6 +402,19 @@ void TreeViewNodeVector::RemoveAt(unsigned int index, bool updateItemsSource)
             source.RemoveAt(index);
         }
     }
+
+    // No children, so close parent if not requested otherwise
+    if (updateIsExpanded && inner->Size() == 0)
+    {
+        if (auto&& ownerNode = m_parent.get())
+        {
+            // Only set IsExpanded to false if we are not the root node
+            if (auto&& ownerParent = ownerNode.Parent())
+            {
+                ownerNode.IsExpanded(false);
+            }
+        }
+    }
 }
 
 void TreeViewNodeVector::RemoveAtEnd(bool updateItemsSource)
@@ -435,7 +448,7 @@ void TreeViewNodeVector::ReplaceAll(winrt::array_view<winrt::TreeViewNode const>
     }
 }
 
-void TreeViewNodeVector::Clear(bool updateItemsSource)
+void TreeViewNodeVector::Clear(bool updateItemsSource,bool updateIsExpanded)
 {
     auto inner = GetVectorInnerImpl();
     auto count = inner->Size();
@@ -458,6 +471,18 @@ void TreeViewNodeVector::Clear(bool updateItemsSource)
             }
         }
     }
+
+    if (updateIsExpanded)
+    {
+        if(auto&& ownerNode = m_parent.get())
+        {
+            // Only set IsExpanded to false if we are not the root node
+            if (auto&& ownerParent = ownerNode.Parent())
+            {
+                ownerNode.IsExpanded(false);
+            }
+        }
+    }
 }
 
 #pragma endregion
diff --git a/dev/TreeView/TreeViewNode.h b/dev/TreeView/TreeViewNode.h
@@ -109,8 +109,8 @@ class TreeViewNodeVector :
     void Append(winrt::TreeViewNode const& item, bool updateItemsSource = true);   
     void InsertAt(unsigned int index, winrt::TreeViewNode const& item, bool updateItemsSource = true);
     void SetAt(unsigned int index, winrt::TreeViewNode const& item, bool updateItemsSource = true);   
-    void RemoveAt(unsigned int index, bool updateItemsSource = true);
+    void RemoveAt(unsigned int index, bool updateItemsSource = true, bool updateIsExpanded = true);
     void RemoveAtEnd(bool updateItemsSource = true);
     void ReplaceAll(winrt::array_view<winrt::TreeViewNode const> values, bool updateItemsSource = true);    
-    void Clear(bool updateItemsSource = true);
+    void Clear(bool updateItemsSource = true, bool updateIsExpanded = true);
 };