feat: use coerce instead of multi binding.

AvaloniaUI · Apr 18, 2024 · 292a1db · 292a1db
1 parent 8356bd8
commit 292a1db
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Showing 5 changed files with 26 additions and 50 deletions.
diff --git a/samples/ControlCatalog/Pages/ComboBoxPage.xaml b/samples/ControlCatalog/Pages/ComboBoxPage.xaml
@@ -118,11 +118,11 @@
                             </StackPanel>
                         </DataTemplate>
                     </ComboBox.ItemTemplate>
-                    <ComboBox.SelectedItemTemplate>
+                    <ComboBox.SelectionBoxItemTemplate>
                         <DataTemplate>
                             <TextBlock Text="{Binding Name}" Foreground="Red"></TextBlock>
                         </DataTemplate>
-                    </ComboBox.SelectedItemTemplate>
+                    </ComboBox.SelectionBoxItemTemplate>
                 </ComboBox>
 
                 <ComboBox WrapSelection="{Binding WrapSelection}" ItemsSource="{Binding Values}" >

diff --git a/src/Avalonia.Controls/ComboBox.cs b/src/Avalonia.Controls/ComboBox.cs
@@ -75,11 +75,21 @@ public class ComboBox : SelectingItemsControl
             ContentControl.VerticalContentAlignmentProperty.AddOwner<ComboBox>();
 
         /// <summary>
-        /// Defines the <see cref="SelectedItemTemplate"/> property.
+        /// Defines the <see cref="SelectionBoxItemTemplate"/> property.
         /// </summary>
-        public static readonly StyledProperty<IDataTemplate?> SelectedItemTemplateProperty =
+        public static readonly StyledProperty<IDataTemplate?> SelectionBoxItemTemplateProperty =
             AvaloniaProperty.Register<ComboBox, IDataTemplate?>(
-                nameof(SelectedItemTemplate), defaultBindingMode: BindingMode.TwoWay);
+                nameof(SelectionBoxItemTemplate), defaultBindingMode: BindingMode.TwoWay, coerce: CoerceSelectionBoxItemTemplate);
+
+        private static IDataTemplate? CoerceSelectionBoxItemTemplate(AvaloniaObject obj, IDataTemplate? template)
+        {
+            if (template is not null) return template;
+            if(obj is ComboBox comboBox && template is null)
+            {
+                return comboBox.ItemTemplate;
+            }
+            return template;
+        }
 
         private Popup? _popup;
         private object? _selectionBoxItem;
@@ -172,10 +182,10 @@ public VerticalAlignment VerticalContentAlignment
         /// Gets or sets the DataTemplate used to display the selected item. This has a higher priority than <see cref="ItemsControl.ItemTemplate"/> if set.
         /// </summary>
         [InheritDataTypeFromItems(nameof(ItemsSource))]
-        public IDataTemplate? SelectedItemTemplate
+        public IDataTemplate? SelectionBoxItemTemplate
         {
-            get => GetValue(SelectedItemTemplateProperty);
-            set => SetValue(SelectedItemTemplateProperty, value);
+            get => GetValue(SelectionBoxItemTemplateProperty);
+            set => SetValue(SelectionBoxItemTemplateProperty, value);
         }
 
         protected override void OnAttachedToVisualTree(VisualTreeAttachmentEventArgs e)
@@ -341,7 +351,10 @@ protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs chang
             {
                 PseudoClasses.Set(pcDropdownOpen, change.GetNewValue<bool>());
             }
-
+            else if (change.Property == ItemTemplateProperty)
+            {
+                CoerceValue(SelectionBoxItemTemplateProperty);
+            }
             base.OnPropertyChanged(change);
         }
 
@@ -452,7 +465,7 @@ private void UpdateSelectionBoxItem(object? item)
             }
             else
             {
-                if(ItemTemplate is null && SelectedItemTemplate is null && DisplayMemberBinding is { } binding)
+                if(ItemTemplate is null && SelectionBoxItemTemplate is null && DisplayMemberBinding is { } binding)
                 {
                     var template = new FuncDataTemplate<object?>((_, _) =>
                     new TextBlock

diff --git a/src/Avalonia.Controls/Converters/MultiDataTemplatesConverter.cs b/src/Avalonia.Controls/Converters/MultiDataTemplatesConverter.cs
diff --git a/src/Avalonia.Themes.Fluent/Controls/ComboBox.xaml b/src/Avalonia.Themes.Fluent/Controls/ComboBox.xaml
@@ -1,7 +1,6 @@
 <ResourceDictionary xmlns="https://github.com/avaloniaui"
                     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                     xmlns:sys="using:System"
-                    xmlns:converters="clr-namespace:Avalonia.Controls.Converters;assembly=Avalonia.Controls"
                     x:ClassModifier="internal">
   <Design.PreviewWith>
     <Border Padding="20">
@@ -37,7 +36,6 @@
   <Thickness x:Key="ComboBoxPadding">12,5,0,7</Thickness>
   <Thickness x:Key="ComboBoxEditableTextPadding">11,5,32,6</Thickness>
   <x:Double x:Key="ComboBoxMinHeight">32</x:Double>
-  <converters:MultiDataTemplatesConverter x:Key="TemplatesConverter"/>
 
   <ControlTheme x:Key="{x:Type ComboBox}" TargetType="ComboBox">
     <Setter Property="Padding" Value="{DynamicResource ComboBoxPadding}" />
@@ -89,13 +87,8 @@
                             Grid.Column="0"
                             Margin="{TemplateBinding Padding}"
                             HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
+                            ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}"
                             VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}">
-              <ContentControl.ContentTemplate>
-                <MultiBinding Converter="{StaticResource TemplatesConverter}">
-                  <TemplateBinding Property="SelectedItemTemplate"></TemplateBinding>
-                  <TemplateBinding Property="ItemTemplate"></TemplateBinding>
-                </MultiBinding>
-              </ContentControl.ContentTemplate>
             </ContentControl>
 
             <Border x:Name="DropDownOverlay"

diff --git a/src/Avalonia.Themes.Simple/Controls/ComboBox.xaml b/src/Avalonia.Themes.Simple/Controls/ComboBox.xaml
@@ -1,8 +1,6 @@
 <ResourceDictionary xmlns="https://github.com/avaloniaui"
                     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-                    xmlns:converters="clr-namespace:Avalonia.Controls.Converters;assembly=Avalonia.Controls"
                     x:ClassModifier="internal">
-  <converters:MultiDataTemplatesConverter x:Key="TemplatesConverter"/>
   <ControlTheme x:Key="{x:Type ComboBox}"
                 TargetType="ComboBox">
     <Setter Property="Background" Value="Transparent" />
@@ -35,13 +33,8 @@
             <ContentControl Margin="{TemplateBinding Padding}"
                             HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
                             VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"
-                            Content="{TemplateBinding SelectionBoxItem}">
-              <ContentControl.ContentTemplate>
-                <MultiBinding Converter="{StaticResource TemplatesConverter}">
-                  <TemplateBinding Property="SelectedItemTemplate"></TemplateBinding>
-                  <TemplateBinding Property="ItemTemplate"></TemplateBinding>
-                </MultiBinding>
-              </ContentControl.ContentTemplate>
+                            Content="{TemplateBinding SelectionBoxItem}"
+                            ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}">
             </ContentControl>
             <ToggleButton Name="toggle"
                           Grid.Column="1"