Merge pull request #4530 from sdoroff/datagrid-details-height

DataGridRowDetails update height on content size change

src/Avalonia.Controls.DataGrid/DataGridRow.cs

@@ -917,23 +917,23 @@ namespace Avalonia.Controls
 
         //TODO Cleanup
         double? _previousDetailsHeight = null;
-
+        
         //TODO Animation 
-        private void DetailsContent_SizeChanged(Rect newValue)
+        private void DetailsContent_HeightChanged(double newValue)
         {
             if (_previousDetailsHeight.HasValue)
             {
                 var oldValue = _previousDetailsHeight.Value;
-                _previousDetailsHeight = newValue.Height;
-                if (newValue.Height != oldValue && newValue.Height != _detailsDesiredHeight)
+                _previousDetailsHeight = newValue;
+                if (newValue != oldValue && newValue != _detailsDesiredHeight)
                 {
 
                     if (AreDetailsVisible && _appliedDetailsTemplate != null)
                     {
                         // Update the new desired height for RowDetails
-                        _detailsDesiredHeight = newValue.Height;
+                        _detailsDesiredHeight = newValue;
 
-                        _detailsElement.ContentHeight = newValue.Height;
+                        _detailsElement.ContentHeight = newValue;
 
                         // Calling this when details are not visible invalidates during layout when we have no work 
                         // to do.  In certain scenarios, this could cause a layout cycle
@@ -943,19 +943,29 @@ namespace Avalonia.Controls
             }
             else
             {
-                _previousDetailsHeight = newValue.Height;
+                _previousDetailsHeight = newValue;
             }
         }
-        private void DetailsContent_BoundsChanged(Rect newValue)
+
+        private void DetailsContent_SizeChanged(Rect newValue)
         {
-            if(_detailsContent != null)
-                DetailsContent_SizeChanged(newValue.Inflate(_detailsContent.Margin));
+            DetailsContent_HeightChanged(newValue.Height);
         }
         private void DetailsContent_MarginChanged(Thickness newValue)
         {
             if (_detailsContent != null)
                 DetailsContent_SizeChanged(_detailsContent.Bounds.Inflate(newValue));
         }
+        private void DetailsContent_LayoutUpdated(object sender, EventArgs e)
+        {
+            if (_detailsContent != null)
+            {
+                var margin = _detailsContent.Margin;
+                var height = _detailsContent.DesiredSize.Height + margin.Top + margin.Bottom;
+
+                DetailsContent_HeightChanged(height);
+            }
+        }
 
         //TODO Animation
         // Sets AreDetailsVisible on the row and animates if necessary
@@ -1035,12 +1045,26 @@ namespace Avalonia.Controls
 
                     if (_detailsContent != null)
                     {
-                        _detailsContentSizeSubscription =
-                            System.Reactive.Disposables.StableCompositeDisposable.Create(
-                                _detailsContent.GetObservable(BoundsProperty)
-                                               .Subscribe(DetailsContent_BoundsChanged),
+                        if (_detailsContent is Layout.Layoutable layoutableContent)
+                        {
+                            layoutableContent.LayoutUpdated += DetailsContent_LayoutUpdated;
+
+                            _detailsContentSizeSubscription =
+                                System.Reactive.Disposables.StableCompositeDisposable.Create(
+                                    System.Reactive.Disposables.Disposable.Create(() => layoutableContent.LayoutUpdated -= DetailsContent_LayoutUpdated),
+                                    _detailsContent.GetObservable(MarginProperty)
+                                                   .Subscribe(DetailsContent_MarginChanged));
+
+
+                        }
+                        else
+                        {
+                            _detailsContentSizeSubscription =
                                 _detailsContent.GetObservable(MarginProperty)
-                                               .Subscribe(DetailsContent_MarginChanged));
+                                               .Subscribe(DetailsContent_MarginChanged);
+
+                        }
+                        
                         _detailsElement.Children.Add(_detailsContent);
                     }
                 }