refactored TableViewColumnHeader initialization logic

Author: w-ahmad

src/TableViewColumnHeader.OptionsFlyoutViewModel.cs

@@ -128,7 +128,7 @@ public IList<TableViewFilterItem> FilterItems
         /// <summary>
         /// Sets the state of the select all checkbox.
         /// </summary>
-        private void SetSelectAllCheckBoxState()
+        internal void SetSelectAllCheckBoxState()
         {
             if (ColumnHeader._selectAllCheckBox is null || !_canSetState)
             {

src/TableViewColumnHeader.cs

@@ -228,24 +228,33 @@ protected override void OnApplyTemplate()
         _optionsButton.Tapped += OnOptionsButtonTaped;
         _optionsButton.DataContext = _optionsFlyoutViewModel = new OptionsFlyoutViewModel(_tableView, this);
 
-        var menuItem = _optionsFlyout.Items.FirstOrDefault(x => x.Name == "ItemsCheckFlyoutItem");
-        menuItem?.ApplyTemplate();
+        if (_optionsFlyout.Items.FirstOrDefault(x => x.Name == "ItemsCheckFlyoutItem") is { } menuItem)
+        {
+            menuItem.Loaded += OnItemsCheckFlyoutItemLoaded;
+        }
+
+        SetFilterButtonVisibility();
+        EnsureGridLines();
+    }
+
+    /// <summary>
+    /// Handles the Loaded event for the items check flyout item.
+    /// </summary>
+    private void OnItemsCheckFlyoutItemLoaded(object sender, RoutedEventArgs e)
+    {
+        if (sender is not MenuFlyoutItem menuItem) return;
+
+        menuItem.Loaded -= OnItemsCheckFlyoutItemLoaded;
 
         if (menuItem?.FindDescendant<CheckBox>(x => x.Name == "SelectAllCheckBox") is { } checkBox)
         {
             _selectAllCheckBox = checkBox;
             _selectAllCheckBox.Content = TableViewLocalizedStrings.SelectAllParenthesized;
             _selectAllCheckBox.Checked += OnSelectAllCheckBoxChecked;
             _selectAllCheckBox.Unchecked += OnSelectAllCheckBoxUnchecked;
+            _optionsFlyoutViewModel.SetSelectAllCheckBoxState();
         }
 
-#if !WINDOWS
-        if (menuItem?.FindDescendant<ListView>(x => x.Name is "FilterItemsList") is { } filterItemsList)
-        {
-            filterItemsList.Margin = new Thickness(12, 0, 0, 0);
-        }
-#endif
-
         if (menuItem?.FindDescendant<TextBox>(x => x.Name == "SearchBox") is { } searchBox)
         {
             _searchBox = searchBox;
@@ -259,9 +268,6 @@ protected override void OnApplyTemplate()
             // Handle Space key to prevent MenuFlyoutItem performing click action.
             menuItem.PreviewKeyUp += static (_, e) => e.Handled = e.Key is VirtualKey.Space;
         }
-
-        SetFilterButtonVisibility();
-        EnsureGridLines();
     }
 
     /// <summary>

src/Themes/TableViewColumnHeader.xaml

@@ -1,9 +1,11 @@
 <ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+                    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
                     xmlns:local="using:WinUI.TableView"
                     xmlns:win="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
-                    xmlns:not_win="http://uno.ui/not_win">
-
+                    xmlns:not_win="http://uno.ui/not_win"
+                    mc:Ignorable="not_win">
+    
     <ResourceDictionary.MergedDictionaries>
         <ResourceDictionary Source="ms-appx:///WinUI.TableView/Themes/Resources.xaml" />
     </ResourceDictionary.MergedDictionaries>
@@ -167,6 +169,7 @@
                                                             <ListView x:Name="FilterItemsList"
                                                                       Grid.Row="2"
                                                                       SelectionMode="None"
+                                                                      not_win:Margin="12,0,0,0"
                                                                       ItemsSource="{Binding FilterItems}">
                                                                 <ListView.ItemContainerStyle>
                                                                     <Style TargetType="ListViewItem"