From f0777a42b919f2c6944fcdf89f71b72442e05280 Mon Sep 17 00:00:00 2001
From: zii-dmg <master-chi@mail.ru>
Date: Fri, 26 Apr 2024 13:06:41 +0300
Subject: [PATCH] Grid fixes (#15516)

* Fixed ShowGridLines = false crash

Fixed "System.InvalidOperationException: 'The control GridLinesRenderer already has a visual parent Grid (Name = grid) while trying to add it as a child of Grid (Name = grid).'" when set ShowGridLines = false and resize.

* Fixed grid lines renderer (fixes ShowGridLines binding)

When changing ShowGridLines property GridLinesRenderer is not updating (create/remove/set bounds). Need to call InvalidateArrange -> ArrangeOverride -> EnsureGridLinesRenderer.
---
 src/Avalonia.Controls/Grid.cs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Avalonia.Controls/Grid.cs b/src/Avalonia.Controls/Grid.cs
index db145b4348..2e745cd364 100644
--- a/src/Avalonia.Controls/Grid.cs
+++ b/src/Avalonia.Controls/Grid.cs
@@ -2325,7 +2325,7 @@ namespace Avalonia.Controls
 
             if ((!ShowGridLines) && (_gridLinesRenderer != null))
             {
-                VisualChildren.Add(_gridLinesRenderer);
+                VisualChildren.Remove(_gridLinesRenderer);
                 _gridLinesRenderer = null;
             }
 
@@ -2357,7 +2357,7 @@ namespace Avalonia.Controls
             if (grid._extData != null    // trivial grid is 1 by 1. there is no grid lines anyway
                 && grid.ListenToNotifications)
             {
-                grid.InvalidateVisual();
+                grid.InvalidateArrange();
             }
 
             grid.SetFlags((bool)e.NewValue!, Flags.ShowGridLinesPropertyValue);