Merge pull request #11227 from rabbitism/combobox

Support DisplayMemberBinding in ComboBox SelectedItem

samples/ControlCatalog/Pages/ComboBoxPage.xaml

@@ -98,6 +98,21 @@
                     <ComboBoxItem>Inline Item 3</ComboBoxItem>
                     <ComboBoxItem>Inline Item 4</ComboBoxItem>
                 </ComboBox>
+
+                <ComboBox WrapSelection="{Binding WrapSelection}" ItemsSource="{Binding Values}" DisplayMemberBinding="{Binding Name}">
+                
+                </ComboBox>
+
+                <ComboBox WrapSelection="{Binding WrapSelection}" ItemsSource="{Binding Values}" >
+                    <ComboBox.ItemTemplate>
+                        <DataTemplate>
+                            <StackPanel Orientation="Horizontal">
+                                <TextBlock Text="{Binding Name}"></TextBlock>
+                                <TextBlock Text="{Binding Id}"></TextBlock>
+                            </StackPanel>
+                        </DataTemplate>
+                    </ComboBox.ItemTemplate>
+                </ComboBox>
             </WrapPanel>
 
             <CheckBox IsChecked="{Binding WrapSelection}">WrapSelection</CheckBox>

samples/ControlCatalog/ViewModels/ComboBoxPageViewModel.cs

@@ -16,5 +16,20 @@ namespace ControlCatalog.ViewModels
             get => _wrapSelection;
             set => this.RaiseAndSetIfChanged(ref _wrapSelection, value);
         }
+
+        public ObservableCollection<IdAndName> Values { get; set; } = new ObservableCollection<IdAndName>
+        {
+            new IdAndName(){ Id = "Id 1", Name = "Name 1" },
+            new IdAndName(){ Id = "Id 2", Name = "Name 2" },
+            new IdAndName(){ Id = "Id 3", Name = "Name 3" },
+            new IdAndName(){ Id = "Id 4", Name = "Name 4" },
+            new IdAndName(){ Id = "Id 5", Name = "Name 5" },
+        };
+    }
+
+    public class IdAndName
+    {
+        public string Id { get; set; }
+        public string Name { get; set; }
     }
 }

src/Avalonia.Controls/ComboBox.cs

@@ -443,7 +443,22 @@ namespace Avalonia.Controls
             }
             else
             {
-                SelectionBoxItem = item;
+                if(ItemTemplate is null && DisplayMemberBinding is { } binding)
+                {
+                    var template = new FuncDataTemplate<object?>((_, _) =>
+                    new TextBlock
+                    {
+                        [TextBlock.DataContextProperty] = item,
+                        [!TextBlock.TextProperty] = binding,
+                    });
+                    var text = template.Build(item);
+                    SelectionBoxItem = text;
+                }
+                else
+                {
+                    SelectionBoxItem = item;
+                }
+                
             }
         }