Pin properties dev tool update

src/Avalonia.Controls.DataGrid/DataGrid.cs

@@ -4161,7 +4161,7 @@ void SetValidationStatus(ICellEditBinding binding)
 
             ResetValidationStatus();
 
-            if (exitEditingMode)
+            if (exitEditingMode && CurrentColumn != null)
             {
                 CurrentColumn.EndCellEditInternal();
                 _editingColumnIndex = -1;

src/Avalonia.Diagnostics/Diagnostics/ViewModels/AvaloniaPropertyViewModel.cs

@@ -7,6 +7,7 @@ internal class AvaloniaPropertyViewModel : PropertyViewModel
     {
         private readonly AvaloniaObject _target;
         private Type _assignedType;
+        private bool _isPinned;
         private object? _value;
         private string _priority;
         private string _group;
@@ -19,6 +20,7 @@ public AvaloniaPropertyViewModel(AvaloniaObject o, AvaloniaProperty property)
         {
             _target = o;
             Property = property;
+            _isPinned = false;
 
             Name = property.IsAttached ?
                 $"[{property.OwnerType.Name}.{property.Name}]" :
@@ -33,6 +35,19 @@ public AvaloniaPropertyViewModel(AvaloniaObject o, AvaloniaProperty property)
         public override string Name { get; }
         public override bool? IsAttached => Property.IsAttached;
         public override string Priority => _priority;
+        public override bool IsPinned
+        {
+            get => _isPinned;
+            set
+            {
+                try
+                {
+                    _isPinned = value;
+                    OnIsPinnedChanged();
+                }
+                catch { }
+            }
+        }
         public override Type AssignedType => _assignedType;
 
         public override object? Value
@@ -56,6 +71,12 @@ public override object? Value
         public override bool IsReadonly => Property.IsReadOnly;
 
         // [MemberNotNull(nameof(_type), nameof(_group), nameof(_priority))]
+        public override event EventHandler IsPinnedChanged;
+
+        protected virtual void OnIsPinnedChanged()
+        {
+            IsPinnedChanged?.Invoke(this, EventArgs.Empty);
+        }
         public override void Update()
         {
             if (Property.IsDirect)

src/Avalonia.Diagnostics/Diagnostics/ViewModels/ClrPropertyViewModel.cs

@@ -7,6 +7,7 @@ internal class ClrPropertyViewModel : PropertyViewModel
     {
         private readonly object _target;
         private Type _assignedType;
+        private bool _isPinned;
         private object? _value;
         private readonly Type _propertyType;
 
@@ -17,6 +18,7 @@ public ClrPropertyViewModel(object o, PropertyInfo property)
         {
             _target = o;
             Property = property;
+            _isPinned = false;
 
             if (property.DeclaringType == null || !property.DeclaringType.IsInterface)
             {
@@ -42,6 +44,28 @@ public ClrPropertyViewModel(object o, PropertyInfo property)
         public override Type PropertyType => _propertyType;
         public override bool IsReadonly => !Property.CanWrite;
 
+        //determines if property is pinned to top in dev tools
+        public override bool IsPinned
+        {
+            get => _isPinned;
+            set
+            {
+                try
+                {
+                    _isPinned = value;
+                    OnIsPinnedChanged();
+                }
+                catch { }
+            }
+        }
+
+        public override event EventHandler IsPinnedChanged;
+
+        protected virtual void OnIsPinnedChanged()
+        {
+            IsPinnedChanged?.Invoke(this, EventArgs.Empty);
+        }
+
         public override object? Value
         {
             get => _value;

src/Avalonia.Diagnostics/Diagnostics/ViewModels/ControlDetailsViewModel.cs

@@ -17,9 +17,13 @@ namespace Avalonia.Diagnostics.ViewModels
     internal class ControlDetailsViewModel : ViewModelBase, IDisposable, IClassesChangedListener
     {
         private readonly AvaloniaObject _avaloniaObject;
+        private int _floatingGridHeight;
+        private List<PropertyViewModel> _pinnedProperties;
+        private DataGridCollectionView? _pinnedPropertiesView;
+        private List<PropertyViewModel> _properties;
+        private DataGridCollectionView? _propertiesView;
         private IDictionary<object, PropertyViewModel[]>? _propertyIndex;
         private PropertyViewModel? _selectedProperty;
-        private DataGridCollectionView? _propertiesView;
         private bool _snapshotStyles;
         private bool _showInactiveStyles;
         private string? _styleStatus;
@@ -32,6 +36,9 @@ internal class ControlDetailsViewModel : ViewModelBase, IDisposable, IClassesCha
         public ControlDetailsViewModel(TreePageViewModel treePage, AvaloniaObject avaloniaObject)
         {
             _avaloniaObject = avaloniaObject;
+            _floatingGridHeight = 0;
+            _pinnedProperties = new List<PropertyViewModel>();
+            _properties = new List<PropertyViewModel>();
 
             TreePage = treePage;
                         Layout =  avaloniaObject is Visual visual 
@@ -160,6 +167,18 @@ public DataGridCollectionView? PropertiesView
             private set => RaiseAndSetIfChanged(ref _propertiesView, value);
         }
 
+        public DataGridCollectionView? PinnedPropertiesView
+        {
+            get => _pinnedPropertiesView;
+            private set => RaiseAndSetIfChanged(ref _pinnedPropertiesView, value);
+        }
+
+        public int FloatingGridHeight
+        {
+            get => _floatingGridHeight;
+            private set => RaiseAndSetIfChanged(ref _floatingGridHeight, value);
+        }
+
         public ObservableCollection<StyleViewModel> AppliedStyles { get; }
 
         public ObservableCollection<PseudoClassViewModel> PseudoClasses { get; }
@@ -481,7 +500,6 @@ public void NavigateToSelectedProperty()
 
             RaisePropertyChanged(nameof(CanNavigateToParentProperty));
         }
-
         public void NavigateToParentProperty()
         {
             if (_selectedEntitiesStack.Count > 0)
@@ -492,7 +510,43 @@ public void NavigateToParentProperty()
                 RaisePropertyChanged(nameof(CanNavigateToParentProperty));
             }
         }
-
+        private void OnPropertyViewModelIsPinnedChanged(object? sender, EventArgs e)
+        {
+            if (sender is PropertyViewModel propertyViewModel)
+            {
+                // CustomPropertyViewModel's IsPinned has changed, handle the change here
+                if (propertyViewModel.IsPinned)
+                {
+                    PinProperty(propertyViewModel);
+                }
+                else
+                {
+                    UnpinProperty(propertyViewModel);
+                }
+            }
+        }
+
+        private void UnpinProperty(PropertyViewModel property)
+        {
+            if (_pinnedProperties.Contains(property))
+            {
+                _pinnedProperties.Remove(property);
+                _properties.Add(property);
+                _pinnedProperties.ToArray();
+                UpdatePropertyViews(_properties.ToArray(),_pinnedProperties.ToArray());
+            }
+        }
+
+        private void PinProperty(PropertyViewModel property)
+        {
+            if (_properties.Contains(property))
+            {
+                _properties.Remove(property);
+                _pinnedProperties.Add(property);
+                UpdatePropertyViews(_properties.ToArray(), _pinnedProperties.ToArray());
+            }
+        }
+
         protected void NavigateToProperty(object o, string? entityName)
         {
             var oldSelectedEntity = SelectedEntity;
@@ -518,15 +572,21 @@ protected void NavigateToProperty(object o, string? entityName)
                 .ThenBy(x => x.Name)
                 .ToArray();
 
-            _propertyIndex = properties
+            _properties = properties.ToList();
+
+            _propertyIndex = _properties
                 .GroupBy(x => x.Key)
                 .ToDictionary(x => x.Key, x => x.ToArray());
 
+            foreach (var propertyViewModelArray in _propertyIndex.Values)
+            {
+                foreach (var propertyViewModel in propertyViewModelArray)
+                {
+                    propertyViewModel.IsPinnedChanged += OnPropertyViewModelIsPinnedChanged;
+                }
+            }
 
-            var view = new DataGridCollectionView(properties);
-            view.GroupDescriptions.Add(new DataGridPathGroupDescription(nameof(AvaloniaPropertyViewModel.Group)));
-            view.Filter = FilterProperty;
-            PropertiesView = view;
+            UpdatePropertyViews(properties, _pinnedProperties.ToArray());
 
             switch (o)
             {
@@ -539,6 +599,35 @@ protected void NavigateToProperty(object o, string? entityName)
                     break;
             }
         }
+
+        private void UpdatePropertyViews(PropertyViewModel?[] unpinnedProperties, PropertyViewModel?[] pinnedProperties)
+        {
+            var view = new DataGridCollectionView(unpinnedProperties);
+            view.GroupDescriptions.Add(new DataGridPathGroupDescription(nameof(AvaloniaPropertyViewModel.Group)));
+            view.Filter = FilterProperty;
+            PropertiesView = view;
+
+            var pinnedView = new DataGridCollectionView(pinnedProperties);
+            pinnedView.GroupDescriptions.Add(new DataGridPathGroupDescription(nameof(AvaloniaPropertyViewModel.Group)));
+            pinnedView.Filter = FilterProperty;
+            PinnedPropertiesView = pinnedView;
+            switch (pinnedProperties.Length)
+            {
+                case 0:
+                    //hide grid
+                    FloatingGridHeight = 0;
+                    break;
+                case 1:
+                    //enough height to show one entry and headers
+                    FloatingGridHeight = 80;
+                    break;
+                default:
+                    //enough height to show two entries and scroll the rest
+                    FloatingGridHeight = 120;
+                    break;
+            }
+
+        }
 
         internal void SelectProperty(AvaloniaProperty property)
         {

src/Avalonia.Diagnostics/Diagnostics/ViewModels/PropertyViewModel.cs

@@ -11,12 +11,14 @@ internal abstract class PropertyViewModel : ViewModelBase
         public abstract string Name { get; }
         public abstract string Group { get; }
         public abstract Type AssignedType { get; }
+        public abstract bool IsPinned { get; set; }
         public abstract Type? DeclaringType { get; }
         public abstract object? Value { get; set; }
         public abstract string Priority { get; }
         public abstract bool? IsAttached { get; }
         public abstract void Update();
         public abstract Type PropertyType { get; }
+        public abstract event EventHandler IsPinnedChanged;
 
         public string Type => PropertyType == AssignedType ?
             PropertyType.GetTypeName() :