Merge pull request #171 from unoplatform/dev/jela/datagrid-loop2

fix(datagrid): Add workaround for layout loop

Author: jeromelaban

CommunityToolkit.WinUI.UI.Controls.DataGrid/DataGrid/DataGrid.cs

@@ -3336,16 +3336,15 @@ protected override Size MeasureOverride(Size availableSize)
             }
             else
             {
-#if !HAS_UNO
-                // This section is commented out in Uno until the measure
-                // loop in uno is adressed
-                if (_rowsPresenter != null)
+                if (DataGridFeatureConfiguation.EnableInvalidateMeasureInMeasureOverride)
                 {
-                    _rowsPresenter.InvalidateMeasure();
-                }
+                    if (_rowsPresenter != null)
+                    {
+                        _rowsPresenter.InvalidateMeasure();
+                    }
 
-                InvalidateColumnHeadersMeasure();
-#endif
+                    InvalidateColumnHeadersMeasure();
+                }
 
                 desiredSize = base.MeasureOverride(availableSize);
 

CommunityToolkit.WinUI.UI.Controls.DataGrid/DataGrid/DataGridFeatureConfiguation.cs

@@ -0,0 +1,21 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace CommunityToolkit.WinUI.UI.Controls
+{
+    /// <summary>
+    /// Uno-specific feature configuration
+    /// </summary>
+    public static class DataGridFeatureConfiguation
+    {
+        /// <summary>
+        /// Gets or sets a value indicating whether if InvalidateMeasure invocations can be done in MeasureOverride locations.
+        /// </summary>
+        /// <remarks>
+        /// This configuration is required until https://github.com/unoplatform/uno/issues/3519 is fixed. Without this
+        /// the layout engine turns into a loop and consumes CPU excessively, or freezes the app.
+        /// </remarks>
+        public static bool EnableInvalidateMeasureInMeasureOverride { get; set; } = false;
+    }
+}

CommunityToolkit.WinUI.UI.Controls.DataGrid/DataGrid/DataGridRow.cs

@@ -780,20 +780,23 @@ protected override Size MeasureOverride(Size availableSize)
                 return base.MeasureOverride(availableSize);
             }
 
-            // Allow the DataGrid specific components to adjust themselves based on new values
-            if (_headerElement != null)
+            if (DataGridFeatureConfiguation.EnableInvalidateMeasureInMeasureOverride)
             {
-                _headerElement.InvalidateMeasure();
-            }
+                // Allow the DataGrid specific components to adjust themselves based on new values
+                if (_headerElement != null)
+                {
+                    _headerElement.InvalidateMeasure();
+                }
 
-            if (_cellsElement != null)
-            {
-                _cellsElement.InvalidateMeasure();
-            }
+                if (_cellsElement != null)
+                {
+                    _cellsElement.InvalidateMeasure();
+                }
 
-            if (_detailsElement != null)
-            {
-                _detailsElement.InvalidateMeasure();
+                if (_detailsElement != null)
+                {
+                    _detailsElement.InvalidateMeasure();
+                }
             }
 
             bool currentAddItemIsDataContext = false;

CommunityToolkit.WinUI.UI.Controls.DataGrid/DataGrid/DataGridRowsPresenter.cs

@@ -133,9 +133,12 @@ protected override Size MeasureOverride(Size availableSize)
                 DataGridRow row = element as DataGridRow;
                 if (row != null)
                 {
-                    if (invalidateRows)
+                    if (DataGridFeatureConfiguation.EnableInvalidateMeasureInMeasureOverride)
                     {
-                        row.InvalidateMeasure();
+                        if (invalidateRows)
+                        {
+                            row.InvalidateMeasure();
+                        }
                     }
                 }