Merge pull request #5211 from donandren/issues/datagridinstackpanel

fix datagrid when in parent StackPanel ( or Grid.Row auto )

src/Avalonia.Controls.DataGrid/Primitives/DataGridRowsPresenter.cs

@@ -3,14 +3,15 @@
 // Please see http://go.microsoft.com/fwlink/?LinkID=131993 for details.
 // All other rights reserved.
 
-using Avalonia.Media;
 using System;
 using System.Diagnostics;
+using Avalonia.Layout;
+using Avalonia.Media;
 
 namespace Avalonia.Controls.Primitives
 {
     /// <summary>
-    /// Used within the template of a <see cref="T:Avalonia.Controls.DataGrid" /> to specify the 
+    /// Used within the template of a <see cref="T:Avalonia.Controls.DataGrid" /> to specify the
     /// location in the control's visual tree where the rows are to be added.
     /// </summary>
     public sealed class DataGridRowsPresenter : Panel
@@ -22,25 +23,10 @@ namespace Avalonia.Controls.Primitives
         }
 
         private double _measureHeightOffset = 0;
-        private double _effectiveViewPortHeight = 0;
-
-        public DataGridRowsPresenter()
-        {
-            EffectiveViewportChanged += OnEffectiveViewportChanged;
-        }
-
-        private void OnEffectiveViewportChanged(object sender, Layout.EffectiveViewportChangedEventArgs e)
-        {
-            if (_effectiveViewPortHeight != e.EffectiveViewport.Height)
-            {
-                _effectiveViewPortHeight = e.EffectiveViewport.Height;
-                InvalidateMeasure();
-            }
-        }
 
         private double CalculateEstimatedAvailableHeight(Size availableSize)
         {
-            if(!Double.IsPositiveInfinity(availableSize.Height))
+            if (!Double.IsPositiveInfinity(availableSize.Height))
             {
                 return availableSize.Height + _measureHeightOffset;
             }
@@ -66,10 +52,10 @@ namespace Avalonia.Controls.Primitives
                 return base.ArrangeOverride(finalSize);
             }
 
-            if(OwningGrid.RowsPresenterAvailableSize.HasValue)
+            if (OwningGrid.RowsPresenterAvailableSize.HasValue)
             {
                 var availableHeight = OwningGrid.RowsPresenterAvailableSize.Value.Height;
-                if(!Double.IsPositiveInfinity(availableHeight))
+                if (!Double.IsPositiveInfinity(availableHeight))
                 {
                     _measureHeightOffset = finalSize.Height - availableHeight;
                     OwningGrid.RowsPresenterEstimatedAvailableHeight = finalSize.Height;
@@ -126,7 +112,14 @@ namespace Avalonia.Controls.Primitives
         {
             if (double.IsInfinity(availableSize.Height))
             {
-                availableSize = availableSize.WithHeight(_effectiveViewPortHeight);
+                if (VisualRoot is TopLevel topLevel)
+                {
+                    double maxHeight = topLevel.IsArrangeValid ?
+                                        topLevel.Bounds.Height :
+                                        LayoutHelper.ApplyLayoutConstraints(topLevel, availableSize).Height;
+
+                    availableSize = availableSize.WithHeight(maxHeight);
+                }
             }
 
             if (availableSize.Height == 0 || OwningGrid == null)