Update TreeView to support blocking drag&drop for specific items (#1646)

* Check 'Handled' for drag drop events

* Add NewParent property in TreeViewDraItemsCompletedEventArgs

* CR feedback

* CR feedback2

* Dummy commit to reset status checks

dev/TreeView/InteractionTests/TreeViewTests.cs

@@ -1898,7 +1898,7 @@ private void TreeViewDragItemTest(bool isContentMode = false)
                 ClickButton("SetupDragDropHandlersForApiTest");
                 UIObject dragUIObject = LabelFirstItem();
                 InputHelper.DragDistance(dragUIObject, dragUIObject.BoundingRectangle.Height, Direction.South);
-                Verify.AreEqual("DragItemsStarting:Root->DragItemsCompleted:Root", ReadResult());
+                Verify.AreEqual("DragItemsStarting:Root\nDragItemsCompleted:Root", ReadResult());
             }
         }
 
@@ -1918,8 +1918,8 @@ public void TreeViewDragItemTest_ContentMode()
 
         private void TreeViewDragMultipleItemsTest(bool isContentMode = false)
         {
-            if (IsPhoneDevice() || IsLowerThanRS2() ||
-              (isContentMode && IsLowerThanRS5()))
+            // InputHelper.DragToTarget() does not work properly on lower versions
+            if (IsLowerThanRS5())
             {
                 return;
             }
@@ -1951,8 +1951,10 @@ private void TreeViewDragMultipleItemsTest(bool isContentMode = false)
 
                 UIObject dragUIObject = FindElement.ByName("Root.0");
                 Verify.IsNotNull(dragUIObject, "Verifying Root.0 is found");
-                InputHelper.DragDistance(dragUIObject, dragUIObject.BoundingRectangle.Height / 2, Direction.South);
-                Verify.AreEqual("DragItemsStarting:Root.0|Root.1->DragItemsCompleted:Root.0|Root.1", ReadResult());
+                UIObject dropUIObject = FindElement.ByName("Root.2");
+                Verify.IsNotNull(dropUIObject, "Verifying Root.2 is found");
+                InputHelper.DragToTarget(dragUIObject, dropUIObject);
+                Verify.AreEqual("DragItemsStarting:Root.0|Root.1\nDragItemsCompleted:Root.0|Root.1\nNewParent: Root.2", ReadResult());
             }
         }
 

dev/TreeView/TestUI/TreeViewPage.xaml.cs

@@ -721,7 +721,14 @@ private void DragItemsStartingForApiTest(TreeView sender, TreeViewDragItemsStart
 
         private void DragItemsCompletedForApiTest(TreeView sender, TreeViewDragItemsCompletedEventArgs args)
         {
-            Results.Text += "->DragItemsCompleted:" + GetDraggedItemsNames(args.Items);
+            Results.Text += "\nDragItemsCompleted:" + GetDraggedItemsNames(args.Items);
+
+            var parent = args.NewParent;
+            if (parent != null)
+            {
+                var parentName = IsInContentMode() ? (parent as TreeViewItemSource).Content : (parent as TreeViewNode).Content.ToString();
+                Results.Text += "\nNewParent: " + parentName;
+            }
         }
 
         private String GetDraggedItemsNames(IEnumerable<object> items)

dev/TreeView/TreeView.cpp

@@ -249,15 +249,29 @@ void TreeView::OnPropertyChanged(const winrt::DependencyPropertyChangedEventArgs
 
 void TreeView::OnListControlDragItemsStarting(const winrt::IInspectable& sender, const winrt::DragItemsStartingEventArgs& args)
 {
-    auto treeViewArgs = winrt::make_self<TreeViewDragItemsStartingEventArgs>();
-    treeViewArgs->DragItemsStartingEventArgs(args);
+    const auto treeViewArgs = winrt::make_self<TreeViewDragItemsStartingEventArgs>(args);
     m_dragItemsStartingEventSource(*this, *treeViewArgs);
 }
 
 void TreeView::OnListControlDragItemsCompleted(const winrt::IInspectable& sender, const winrt::DragItemsCompletedEventArgs& args)
 {
-    auto treeViewArgs = winrt::make_self<TreeViewDragItemsCompletedEventArgs>();
-    treeViewArgs->DragItemsCompletedEventArgs(args);
+    const auto newParent = [items = args.Items(), listControl = ListControl(), rootNode = m_rootNode.get()]()
+    {
+        if (listControl && items && items.Size() > 0)
+        {
+            if (const auto draggedNode = listControl->NodeFromItem(items.GetAt(0)))
+            {
+                const auto parentNode = draggedNode.Parent();
+                if (parentNode && parentNode != rootNode)
+                {
+                    return listControl->ItemFromNode(parentNode);
+                }
+            }
+        }
+        return static_cast<winrt::IInspectable>(nullptr);
+    }();
+
+    const auto treeViewArgs = winrt::make_self<TreeViewDragItemsCompletedEventArgs>(args, newParent);
     m_dragItemsCompletedEventSource(*this, *treeViewArgs);
 }
 

dev/TreeView/TreeView.idl

@@ -87,6 +87,11 @@ runtimeclass TreeViewDragItemsCompletedEventArgs
 {
     Windows.ApplicationModel.DataTransfer.DataPackageOperation DropResult{ get; };
     Windows.Foundation.Collections.IVectorView<Object> Items{ get; };
+
+    [WUXC_VERSION_PREVIEW]
+    {
+        Object NewParent{ get; };
+    }
 }
 
 [WUXC_VERSION_RS4]

dev/TreeView/TreeViewDragItemsCompletedEventArgs.cpp

@@ -6,11 +6,13 @@
 #include "Vector.h"
 #include "TreeViewDragItemsCompletedEventArgs.h"
 
-void TreeViewDragItemsCompletedEventArgs::DragItemsCompletedEventArgs(const winrt::DragItemsCompletedEventArgs& args)
+TreeViewDragItemsCompletedEventArgs::TreeViewDragItemsCompletedEventArgs(const winrt::DragItemsCompletedEventArgs& args, const winrt::IInspectable& newParent)
 {
     m_dragItemsCompletedEventArgs = args;
+    m_newParent = newParent;
 }
 
+
 DataPackageOperation TreeViewDragItemsCompletedEventArgs::DropResult() const
 {
     return m_dragItemsCompletedEventArgs.DropResult();
@@ -19,4 +21,9 @@ DataPackageOperation TreeViewDragItemsCompletedEventArgs::DropResult() const
 winrt::IVectorView<winrt::IInspectable> TreeViewDragItemsCompletedEventArgs::Items()
 {
     return m_dragItemsCompletedEventArgs.Items();
-}
+}
+
+winrt::IInspectable TreeViewDragItemsCompletedEventArgs::NewParent()
+{
+    return m_newParent;
+}

dev/TreeView/TreeViewDragItemsCompletedEventArgs.h

@@ -10,10 +10,12 @@ class TreeViewDragItemsCompletedEventArgs :
     public ReferenceTracker<TreeViewDragItemsCompletedEventArgs, winrt::implementation::TreeViewDragItemsCompletedEventArgsT, winrt::composing, winrt::composable>
 {
 public:
-    void DragItemsCompletedEventArgs(const winrt::DragItemsCompletedEventArgs& args);
+    TreeViewDragItemsCompletedEventArgs(const winrt::DragItemsCompletedEventArgs& args, const winrt::IInspectable& newParent);
     DataPackageOperation DropResult() const;
     winrt::IVectorView<winrt::IInspectable> Items();
+    winrt::IInspectable NewParent();
 
 private:
     winrt::DragItemsCompletedEventArgs m_dragItemsCompletedEventArgs{ nullptr };
-};
+    winrt::IInspectable m_newParent;
+};

dev/TreeView/TreeViewDragItemsStartingEventArgs.cpp

@@ -6,7 +6,7 @@
 #include "Vector.h"
 #include "TreeViewDragItemsStartingEventArgs.h"
 
-void TreeViewDragItemsStartingEventArgs::DragItemsStartingEventArgs(const winrt::DragItemsStartingEventArgs& args)
+TreeViewDragItemsStartingEventArgs::TreeViewDragItemsStartingEventArgs(const winrt::DragItemsStartingEventArgs& args)
 {
     m_dragItemsStartingEventArgs = args;
 }
@@ -29,4 +29,4 @@ DataPackage TreeViewDragItemsStartingEventArgs::Data() const
 winrt::IVector<winrt::IInspectable> TreeViewDragItemsStartingEventArgs::Items()
 {
     return m_dragItemsStartingEventArgs.Items();
-}
+}

dev/TreeView/TreeViewDragItemsStartingEventArgs.h

@@ -9,7 +9,7 @@ class TreeViewDragItemsStartingEventArgs :
     public ReferenceTracker<TreeViewDragItemsStartingEventArgs, winrt::implementation::TreeViewDragItemsStartingEventArgsT, winrt::composing, winrt::composable>
 {
 public:
-    void DragItemsStartingEventArgs(const winrt::DragItemsStartingEventArgs& args);
+    TreeViewDragItemsStartingEventArgs(const winrt::DragItemsStartingEventArgs& args);
     bool Cancel() const;
     void Cancel(const bool value);
     DataPackage Data() const;

dev/TreeView/TreeViewItem.cpp

@@ -66,7 +66,7 @@ void TreeViewItem::OnKeyDown(winrt::KeyRoutedEventArgs const& e)
 
 void TreeViewItem::OnDrop(winrt::DragEventArgs const& args)
 {
-    if (args.AcceptedOperation() == winrt::Windows::ApplicationModel::DataTransfer::DataPackageOperation::Move)
+    if (!args.Handled() && args.AcceptedOperation() == winrt::Windows::ApplicationModel::DataTransfer::DataPackageOperation::Move)
     {
         winrt::TreeViewItem droppedOnItem = *this;
         auto treeView = AncestorTreeView();
@@ -127,7 +127,7 @@ void TreeViewItem::OnDrop(winrt::DragEventArgs const& args)
 void TreeViewItem::OnDragOver(winrt::DragEventArgs const& args)
 {
     auto treeView = AncestorTreeView();
-    if (treeView)
+    if (treeView && !args.Handled())
     {
         auto treeViewList = treeView->ListControl();
         winrt::TreeViewItem draggedOverItem = *this;
@@ -179,7 +179,7 @@ void TreeViewItem::OnDragEnter(winrt::DragEventArgs const& args)
     args.DragUIOverride().IsGlyphVisible(true);
 
     auto treeView = AncestorTreeView();
-    if (treeView && treeView->CanReorderItems())
+    if (treeView && treeView->CanReorderItems() && !args.Handled())
     {
         auto treeViewList = treeView->ListControl();
         winrt::TreeViewNode draggedNode = treeViewList->DraggedTreeViewNode();
@@ -230,15 +230,18 @@ void TreeViewItem::OnDragEnter(winrt::DragEventArgs const& args)
 
 void TreeViewItem::OnDragLeave(winrt::DragEventArgs const& args)
 {
-    if (auto treeView = AncestorTreeView())
+    if (!args.Handled())
     {
-        auto treeViewList = treeView->ListControl();
-        treeViewList->SetDraggedOverItem(nullptr);
-    }
+        if (auto treeView = AncestorTreeView())
+        {
+            auto treeViewList = treeView->ListControl();
+            treeViewList->SetDraggedOverItem(nullptr);
+        }
 
-    if (m_expandContentTimer)
-    {
-        m_expandContentTimer.get().Stop();
+        if (m_expandContentTimer)
+        {
+            m_expandContentTimer.get().Stop();
+        }
     }
 
     __super::OnDragLeave(args);