Merge pull request #4685 from Kir-Antipov/enhanced-autocomplete

Enhanced AutoCompleteBox

samples/ControlCatalog/Pages/AutoCompleteBoxPage.xaml

@@ -51,6 +51,11 @@
                          Width="200"
                          Margin="0,0,0,8"
                          FilterMode="None"/>
+        <TextBlock Text="Custom Autocomplete"/>
+        <AutoCompleteBox Name="CustomAutocompleteBox"
+                         Width="200"
+                         Margin="0,0,0,8"
+                         FilterMode="None"/>
       </StackPanel>
     </StackPanel>
   </StackPanel>

samples/ControlCatalog/Pages/AutoCompleteBoxPage.xaml.cs

@@ -92,13 +92,28 @@ namespace ControlCatalog.Pages
         }
         public StateData[] States { get; private set; }
         
+        private LinkedList<string>[] BuildAllSentences()
+        {
+            return new string[]
+            {
+                "Hello world",
+                "No this is Patrick",
+                "Never gonna give you up",
+                "How does one patch KDE2 under FreeBSD"
+            }
+            .Select(x => new LinkedList<string>(x.Split(' ')))
+            .ToArray();
+        }
+        public LinkedList<string>[] Sentences { get; private set; }
+
         public AutoCompleteBoxPage()
         {
             this.InitializeComponent();
 
             States = BuildAllStates();
+            Sentences = BuildAllSentences();
 
-            foreach (AutoCompleteBox box in GetAllAutoCompleteBox())
+            foreach (AutoCompleteBox box in GetAllAutoCompleteBox().Where(x => x.Name != "CustomAutocompleteBox"))
             {
                 box.Items = States;
             }
@@ -116,6 +131,11 @@ namespace ControlCatalog.Pages
 
             var asyncBox = this.FindControl<AutoCompleteBox>("AsyncBox");
             asyncBox.AsyncPopulator = PopulateAsync;
+
+            var customAutocompleteBox = this.FindControl<AutoCompleteBox>("CustomAutocompleteBox");
+            customAutocompleteBox.Items = Sentences.SelectMany(x => x);
+            customAutocompleteBox.TextFilter = LastWordContains;
+            customAutocompleteBox.TextSelector = AppendWord;
         }
         private IEnumerable<AutoCompleteBox> GetAllAutoCompleteBox()
         {
@@ -137,6 +157,42 @@ namespace ControlCatalog.Pages
                       .ToList();
         }
 
+        private bool LastWordContains(string searchText, string item)
+        {
+            var words = searchText.Split(' ');
+            var options = Sentences.Select(x => x.First).ToArray();
+            for (var i = 0; i < words.Length; ++i)
+            {
+                var word = words[i];
+                for (var j = 0; j < options.Length; ++j)
+                {
+                    var option = options[j];
+                    if (option == null)
+                        continue;
+
+                    if (i == words.Length - 1)
+                    {
+                        options[j] = option.Value.ToLower().Contains(word.ToLower()) ? option : null;
+                    }
+                    else
+                    {
+                        options[j] = option.Value.Equals(word, StringComparison.InvariantCultureIgnoreCase) ? option.Next : null;
+                    }
+                }
+            }
+
+            return options.Any(x => x != null && x.Value == item);
+        }
+        private string AppendWord(string text, string item)
+        {
+            string[] parts = text.Split(' ');
+            if (parts.Length == 0)
+                return item;
+
+            parts[parts.Length - 1] = item;
+            return string.Join(" ", parts);
+        }
+
         private void InitializeComponent()
         {
             AvaloniaXamlLoader.Load(this);

src/Avalonia.Controls/AutoCompleteBox.cs

@@ -227,6 +227,27 @@ namespace Avalonia.Controls
         Custom = 13,
     }
 
+    /// <summary>
+    /// Represents the selector used by the
+    /// <see cref="T:Avalonia.Controls.AutoCompleteBox" /> control to
+    /// determine how the specified text should be modified with an item.
+    /// </summary>
+    /// <returns>
+    /// Modified text that will be used by the
+    /// <see cref="T:Avalonia.Controls.AutoCompleteBox" />.
+    /// </returns>
+    /// <param name="search">The string used as the basis for filtering.</param>
+    /// <param name="item">
+    /// The selected item that should be combined with the
+    /// <paramref name="search" /> parameter.
+    /// </param>
+    /// <typeparam name="T">
+    /// The type used for filtering the
+    /// <see cref="T:Avalonia.Controls.AutoCompleteBox" />.
+    /// This type can be either a string or an object.
+    /// </typeparam>
+    public delegate string AutoCompleteSelector<T>(string search, T item);
+
     /// <summary>
     /// Represents a control that provides a text box for user input and a
     /// drop-down that contains possible matches based on the input in the text
@@ -364,6 +385,9 @@ namespace Avalonia.Controls
         private AutoCompleteFilterPredicate<object> _itemFilter;
         private AutoCompleteFilterPredicate<string> _textFilter = AutoCompleteSearch.GetFilter(AutoCompleteFilterMode.StartsWith);
 
+        private AutoCompleteSelector<object> _itemSelector;
+        private AutoCompleteSelector<string> _textSelector;
+
         public static readonly RoutedEvent<SelectionChangedEventArgs> SelectionChangedEvent =
             RoutedEvent.Register<SelectionChangedEventArgs>(nameof(SelectionChanged), RoutingStrategies.Bubble, typeof(AutoCompleteBox));
 
@@ -530,6 +554,34 @@ namespace Avalonia.Controls
                 (o, v) => o.TextFilter = v,
                 unsetValue: AutoCompleteSearch.GetFilter(AutoCompleteFilterMode.StartsWith));
 
+        /// <summary>
+        /// Identifies the
+        /// <see cref="P:Avalonia.Controls.AutoCompleteBox.ItemSelector" />
+        /// dependency property.
+        /// </summary>
+        /// <value>The identifier for the
+        /// <see cref="P:Avalonia.Controls.AutoCompleteBox.ItemSelector" />
+        /// dependency property.</value>
+        public static readonly DirectProperty<AutoCompleteBox, AutoCompleteSelector<object>> ItemSelectorProperty =
+            AvaloniaProperty.RegisterDirect<AutoCompleteBox, AutoCompleteSelector<object>>(
+                nameof(ItemSelector),
+                o => o.ItemSelector,
+                (o, v) => o.ItemSelector = v);
+
+        /// <summary>
+        /// Identifies the
+        /// <see cref="P:Avalonia.Controls.AutoCompleteBox.TextSelector" />
+        /// dependency property.
+        /// </summary>
+        /// <value>The identifier for the
+        /// <see cref="P:Avalonia.Controls.AutoCompleteBox.TextSelector" />
+        /// dependency property.</value>
+        public static readonly DirectProperty<AutoCompleteBox, AutoCompleteSelector<string>> TextSelectorProperty =
+            AvaloniaProperty.RegisterDirect<AutoCompleteBox, AutoCompleteSelector<string>>(
+                nameof(TextSelector),
+                o => o.TextSelector,
+                (o, v) => o.TextSelector = v);
+
         /// <summary>
         /// Identifies the
         /// <see cref="P:Avalonia.Controls.AutoCompleteBox.ItemsSource" />
@@ -1063,6 +1115,40 @@ namespace Avalonia.Controls
             set { SetAndRaise(TextFilterProperty, ref _textFilter, value); }
         }
 
+        /// <summary>
+        /// Gets or sets the custom method that combines the user-entered
+        /// text and one of the items specified by the
+        /// <see cref="P:Avalonia.Controls.AutoCompleteBox.ItemsSource" />.
+        /// </summary>
+        /// <value>
+        /// The custom method that combines the user-entered
+        /// text and one of the items specified by the
+        /// <see cref="P:Avalonia.Controls.AutoCompleteBox.ItemsSource" />.
+        /// </value>
+        public AutoCompleteSelector<object> ItemSelector
+        {
+            get { return _itemSelector; }
+            set { SetAndRaise(ItemSelectorProperty, ref _itemSelector, value); }
+        }
+
+        /// <summary>
+        /// Gets or sets the custom method that combines the user-entered
+        /// text and one of the items specified by the
+        /// <see cref="P:Avalonia.Controls.AutoCompleteBox.ItemsSource" />
+        /// in a text-based way.
+        /// </summary>
+        /// <value>
+        /// The custom method that combines the user-entered
+        /// text and one of the items specified by the
+        /// <see cref="P:Avalonia.Controls.AutoCompleteBox.ItemsSource" />
+        /// in a text-based way.
+        /// </value>
+        public AutoCompleteSelector<string> TextSelector
+        {
+            get { return _textSelector; }
+            set { SetAndRaise(TextSelectorProperty, ref _textSelector, value); }
+        }
+
         public Func<string, CancellationToken, Task<IEnumerable<object>>> AsyncPopulator
         {
             get { return _asyncPopulator; }
@@ -2331,6 +2417,14 @@ namespace Avalonia.Controls
             {
                 text = SearchText;
             }
+            else if (TextSelector != null)
+            {
+                text = TextSelector(SearchText, FormatValue(newItem, true));
+            }
+            else if (ItemSelector != null)
+            {
+                text = ItemSelector(SearchText, newItem);
+            }
             else
             {
                 text = FormatValue(newItem, true);

tests/Avalonia.Controls.UnitTests/AutoCompleteBoxTests.cs

@@ -363,6 +363,40 @@ namespace Avalonia.Controls.UnitTests
             });
         }
         
+        [Fact]
+        public void Custom_TextSelector()
+        {
+            RunTest((control, textbox) =>
+            {
+                object selectedItem = control.Items.Cast<object>().First();
+                string input = "42";
+
+                control.TextSelector = (text, item) => text + item;
+                Assert.Equal(control.TextSelector("4", "2"), "42");
+
+                control.Text = input;
+                control.SelectedItem = selectedItem;
+                Assert.Equal(control.Text, control.TextSelector(input, selectedItem.ToString()));
+            });
+        }
+        
+        [Fact]
+        public void Custom_ItemSelector()
+        {
+            RunTest((control, textbox) =>
+            {
+                object selectedItem = control.Items.Cast<object>().First();
+                string input = "42";
+
+                control.ItemSelector = (text, item) => text + item;
+                Assert.Equal(control.ItemSelector("4", 2), "42");
+
+                control.Text = input;
+                control.SelectedItem = selectedItem;
+                Assert.Equal(control.Text, control.ItemSelector(input, selectedItem));
+            });
+        }
+
         /// <summary>
         /// Retrieves a defined predicate filter through a new AutoCompleteBox 
         /// control instance.