From 5116379b537b45a7df5dc6a4a1737657b737b22b Mon Sep 17 00:00:00 2001
From: Dilip Ojha <dilip.ojha@microsoft.com>
Date: Wed, 25 May 2022 16:46:16 -0700
Subject: [PATCH] disable virtualization fixes (#7142)

---
 dev/NavigationView/NavigationViewItem.cpp |  7 +++++++
 dev/Repeater/FlowLayoutAlgorithm.cpp      | 10 +++++++---
 dev/Repeater/FlowLayoutAlgorithm.h        |  1 +
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/dev/NavigationView/NavigationViewItem.cpp b/dev/NavigationView/NavigationViewItem.cpp
index c161cb3c17..039690616b 100644
--- a/dev/NavigationView/NavigationViewItem.cpp
+++ b/dev/NavigationView/NavigationViewItem.cpp
@@ -7,6 +7,7 @@
 #include "NavigationView.h"
 #include "NavigationViewItem.h"
 #include "NavigationViewItemAutomationPeer.h"
+#include "StackLayout.h"
 #include "Utils.h"
 
 static constexpr wstring_view c_navigationViewItemPresenterName = L"NavigationViewItemPresenter"sv;
@@ -156,6 +157,12 @@ void NavigationViewItem::LoadMenuItemsHost()
         {
             m_repeater.set(repeater);
 
+            if (auto stackLayout = repeater.Layout().try_as<winrt::StackLayout>())
+            {
+                auto stackLayoutImpl = winrt::get_self<StackLayout>(stackLayout);
+                stackLayoutImpl->DisableVirtualization(true);
+            }
+
             // Primary element setup happens in NavigationView
             m_repeaterElementPreparedRevoker = repeater.ElementPrepared(winrt::auto_revoke, { nvImpl,  &NavigationView::OnRepeaterElementPrepared });
             m_repeaterElementClearingRevoker = repeater.ElementClearing(winrt::auto_revoke, { nvImpl, &NavigationView::OnRepeaterElementClearing });
diff --git a/dev/Repeater/FlowLayoutAlgorithm.cpp b/dev/Repeater/FlowLayoutAlgorithm.cpp
index 8af0e7d777..733cc2c891 100644
--- a/dev/Repeater/FlowLayoutAlgorithm.cpp
+++ b/dev/Repeater/FlowLayoutAlgorithm.cpp
@@ -58,9 +58,12 @@ winrt::Size FlowLayoutAlgorithm::Measure(
         }
     }
 
-    m_elementManager.OnBeginMeasure(orientation);
+    if(!disableVirtualization)
+    {
+        m_elementManager.OnBeginMeasure(orientation);
+    }
 
-    const int anchorIndex = GetAnchorIndex(availableSize, isWrapping, minItemSpacing, layoutId);
+    const int anchorIndex = GetAnchorIndex(availableSize, isWrapping, minItemSpacing, disableVirtualization, layoutId);
     Generate(GenerateDirection::Forward, anchorIndex, availableSize, minItemSpacing, lineSpacing, maxItemsPerLine, disableVirtualization, layoutId);
     Generate(GenerateDirection::Backward, anchorIndex, availableSize, minItemSpacing, lineSpacing, maxItemsPerLine, disableVirtualization, layoutId);
     if (isWrapping && IsReflowRequired())
@@ -147,13 +150,14 @@ int FlowLayoutAlgorithm::GetAnchorIndex(
     const winrt::Size& availableSize,
     bool isWrapping,
     double minItemSpacing,
+    const bool disableVirtualization,
     const wstring_view& layoutId)
 {
     int anchorIndex = -1;
     winrt::Point anchorPosition{};
     auto context = m_context.get();
 
-    if (!IsVirtualizingContext())
+    if (!IsVirtualizingContext() || disableVirtualization)
     {
         // Non virtualizing host, start generating from the element 0
         anchorIndex = context.ItemCountCore() > 0 ? 0 : -1;
diff --git a/dev/Repeater/FlowLayoutAlgorithm.h b/dev/Repeater/FlowLayoutAlgorithm.h
index 87be9c89ac..0d0ea3162f 100644
--- a/dev/Repeater/FlowLayoutAlgorithm.h
+++ b/dev/Repeater/FlowLayoutAlgorithm.h
@@ -77,6 +77,7 @@ class FlowLayoutAlgorithm : OrientationBasedMeasures
         const winrt::Size& availableSize,
         bool isWrapping,
         double minItemSpacing,
+        const bool disableVirtualization,
         const wstring_view& layoutId);
     void Generate(
         GenerateDirection direction,