Expand/collapse rows recursively when shift is held.

Author: ernstaii

DsmSuite.DsmViewer.Model/Core/DsmElement.cs

@@ -95,6 +95,16 @@ public string GetRelativeName(IDsmElement element)
 
         public bool IsExpanded { get; set; }
 
+        public void ExpandRecursively(bool expanded)
+        {
+            if (!HasChildren)
+                return;
+
+            IsExpanded = expanded;
+            foreach (DsmElement child in Children)
+                child.ExpandRecursively(expanded);
+        }
+
         public bool IsMatch { get; set; }
 
         public bool IsIncludedInTree { get; set; }

DsmSuite.DsmViewer.Model/Interfaces/IDsmElement.cs

@@ -43,12 +43,12 @@ public interface IDsmElement : IComparable
         bool IsRoot { get; }
 
         /// <summary>
-        /// Has the element any children that are in the tree.
+        /// Has the element any children that are in the tree (see <see cref="IsIncludedInTree"/>).
         /// </summary>
         bool HasChildren { get; }
 
         /// <summary>
-        /// Tree children of the element.
+        /// Tree children of the element (see <see cref="IsIncludedInTree"/>).
         /// </summary>
         IList<IDsmElement> Children { get; }
 
@@ -69,17 +69,29 @@ public interface IDsmElement : IComparable
         bool IsRecursiveChildOf(IDsmElement element);
 
         /// <summary>
-        /// Is the element expanded in the viewer.
+        /// Is the element expanded in the viewer. This is only meaningful for elements with children.<br/>
+        /// If an element is expanded, each of its children has a line in the matrix and the element
+        /// itself hasn't, but is used to vertically group the children.<br/>
+        /// If an element is not expanded, its children are not displayed and the element itself has
+        /// a row in the matrix.<br/>
+        /// This property is only relevant and should only be changed for elements that are in the
+        /// tree (see <see cref="IsIncludedInTree"/>).
         /// </summary>
         bool IsExpanded { get; set; }
 
+        /// <summary>
+        /// Set or clear the IsExpanded property recursively for elements in the tree.
+        /// </summary>
+        void ExpandRecursively(bool expanded);
+
         /// <summary>
         /// Is the element match in search.
         /// </summary>
         bool IsMatch{ get; set; }
 
         /// <summary>
-        /// Is the element included in the tree
+        /// Is the element included in the tree. The tree is the set of elements that are in scope
+        /// for the viewer, i.e. that are not filtered out.
         /// </summary>
         bool IsIncludedInTree { get; set; }
     }

DsmSuite.DsmViewer.View/Matrix/MatrixRowHeaderView.cs

@@ -59,7 +59,7 @@ private void OnMouseDown(object sender, MouseButtonEventArgs e)
 
                 if (e.ChangedButton == MouseButton.Left  &&  pt.X < 20  &&  pt.Y < 24)
                 {
-                    _matrixViewModel.ToggleElementExpandedCommand.Execute(null);
+                    _matrixViewModel.ToggleElementExpandedCommand.Execute(Keyboard.Modifiers == ModifierKeys.Shift);
                     InvalidateVisual();
                 }
             }

DsmSuite.DsmViewer.ViewModel/Main/MainViewModel.cs

@@ -426,13 +426,22 @@ private bool ZoomOutCanExecute(object parameter)
             return ActiveMatrix?.ZoomLevel > _minZoom;
         }
 
-        private void ToggleElementExpandedExecute(object parameter)
+        /// <summary>
+        /// Toggle the IsExpanded state of the current row. If <paramref name="recursive"/> is
+        /// <c>bool true</c>, the IsExpanded state of the entire subtree under the current element
+        /// is set to the same new value as element.
+        /// If <paramref name="recursive"/> is false, only the current element is toggled.
+        /// </summary>
+        private void ToggleElementExpandedExecute(object recursive)
         {
             ElementTreeItemViewModel vm = ActiveMatrix.FindElementViewModel(ActiveMatrix.HoveredRow?.Element);
-            if (vm != null  &&  vm.IsExpandable)
-            {
-                vm.IsExpanded = !vm.IsExpanded;
-            }
+            if (vm == null  ||  !vm.IsExpandable)
+                return;
+
+            if ((bool)recursive)
+                vm.Element.ExpandRecursively(!vm.IsExpanded);
+            else
+                vm.Element.IsExpanded = !vm.IsExpanded;
 
             ActiveMatrix.Reload();
         }

DsmSuite.DsmViewer.ViewModel/Matrix/ElementTreeItemViewModel.cs

@@ -72,17 +72,8 @@ public MatrixColor Color
 
         public bool IsExpandable => Element.HasChildren;
 
-        public bool IsExpanded
-        {
-            get
-            {
-                return Element.IsExpanded;
-            }
-            set
-            {
-                Element.IsExpanded = value;
-            }
-        }
+        public bool IsExpanded => Element.IsExpanded;
+
 
         public IReadOnlyList<ElementTreeItemViewModel> Children => _children;
 

README.md

@@ -20,6 +20,8 @@ Settings are read and saved from %APPDATA%, usually `%HOME%/AppData/{Local,Roami
 Several smallish changes to the functionality were made; see Changes below.
 Larger changes are described in the remainder of this section.
 
+* Expanding or collapsing a row header with shift pressed will expand or collapse recursively.
+
 
 ### Snapshots
 Snapshots are saved as part of the action list with the model. You can return to a snapshot by selecting it from the dropdown list (narrow down-triangle) next to the action button.
@@ -37,6 +39,7 @@ A snapshot is a marker in the undo/redo list. This has some important consequenc
 * 24-08-28 Show current selection in legend.
 * 25-02-15 Filtering is an action and can be undone and saved.
 * 25-03-09 A dropdown list next to the 'Make snapshot' button allows jumping back to a snapshot.
+* 25-03-23 Expand/collapse recursively with shift.
 
 ## Implementation notes