Added SelectedItemsControl.SelectedIndex

Perspex.Controls/Primitives/SelectingItemsControl.cs

@@ -11,9 +11,13 @@ namespace Perspex.Controls.Primitives
     using System.Linq;
     using Perspex.Input;
     using Perspex.VisualTree;
+    using System.Collections.Generic;
 
     public abstract class SelectingItemsControl : ItemsControl
     {
+        public static readonly PerspexProperty<int> SelectedIndexProperty =
+            PerspexProperty.Register<SelectingItemsControl, int>("SelectedIndex", coerce: CoerceSelectedIndex);
+
         public static readonly PerspexProperty<object> SelectedItemProperty =
             PerspexProperty.Register<SelectingItemsControl, object>("SelectedItem");
 
@@ -21,6 +25,16 @@ namespace Perspex.Controls.Primitives
         {
             FocusableProperty.OverrideDefaultValue(typeof(SelectingItemsControl), true);
 
+            SelectedIndexProperty.Changed.Subscribe(x =>
+            {
+                var control = x.Sender as SelectingItemsControl;
+
+                if (control != null)
+                {
+                    control.SelectedItem = control.GetItemAt((int)x.NewValue);
+                }
+            });
+
             SelectedItemProperty.Changed.Subscribe(x =>
             {
                 var control = x.Sender as SelectingItemsControl;
@@ -32,6 +46,12 @@ namespace Perspex.Controls.Primitives
             });
         }
 
+        public int SelectedIndex
+        {
+            get { return this.GetValue(SelectedIndexProperty); }
+            set { this.SetValue(SelectedIndexProperty, value); }
+        }
+
         public object SelectedItem
         {
             get { return this.GetValue(SelectedItemProperty); }
@@ -40,7 +60,13 @@ namespace Perspex.Controls.Primitives
 
         protected static int GetIndexOfItem(IEnumerable items, object item)
         {
-            if (items != null)
+            var list = items as IList;
+
+            if (list != null)
+            {
+                return list.IndexOf(item);
+            }
+            else if (items != null)
             {
                 int index = 0;
 
@@ -58,11 +84,32 @@ namespace Perspex.Controls.Primitives
             return -1;
         }
 
+        protected static object GetItemAt(IEnumerable items, int index)
+        {
+            var list = items as IList;
+
+            if (list != null)
+            {
+                return list[index];
+            }
+            else if (items != null)
+            {
+                return items.Cast<object>().ElementAt(index);
+            }
+
+            return -1;
+        }
+
         protected int GetIndexOfItem(object item)
         {
             return GetIndexOfItem(this.Items, item);
         }
 
+        protected object GetItemAt(int index)
+        {
+            return GetItemAt(this.Items, index);
+        }
+
         protected virtual void MoveSelection(FocusNavigationDirection direction)
         {
             var panel = this.Presenter?.Panel as INavigablePanel;
@@ -150,6 +197,26 @@ namespace Perspex.Controls.Primitives
             e.Handled = true;
         }
 
+        private static int CoerceSelectedIndex(PerspexObject o, int value)
+        {
+            var control = o as SelectingItemsControl;
+
+            if (control != null)
+            {
+                if (value < -1)
+                {
+                    return -1;
+                }
+                else if (value > -1)
+                {
+                    var count = control.Items.Cast<object>().Count();
+                    return Math.Min(value, count - 1);
+                }
+            }
+
+            return value;
+        }
+
         private void SelectedItemChanged(object selected)
         {
             var containers = this.ItemContainerGenerator.GetAll()
@@ -168,6 +235,15 @@ namespace Perspex.Controls.Primitives
             {
                 item.IsSelected = item == selectedContainer;
             }
+
+            if (selected == null)
+            {
+                this.SelectedIndex = -1;
+            }
+            else
+            {
+                this.SelectedIndex = GetIndexOfItem(selected);
+            }
         }
     }
 }

Tests/Perspex.Controls.UnitTests/Perspex.Controls.UnitTests.csproj

@@ -92,7 +92,7 @@
     <Compile Include="DropDownTests.cs" />
     <Compile Include="ScrollContentPresenterTests.cs" />
     <Compile Include="ScrollViewerTests.cs" />
-    <Compile Include="SelectingItemsControlTests.cs" />
+    <Compile Include="Primitives\SelectingItemsControlTests.cs" />
     <Compile Include="ListBoxTests.cs" />
     <Compile Include="ItemsControlTests.cs" />
     <Compile Include="ContentControlTests.cs" />

Tests/Perspex.Controls.UnitTests/Primitives/SelectingItemsControlTests.cs

@@ -0,0 +1,154 @@
+// -----------------------------------------------------------------------
+// <copyright file="SelectingItemsControlTests.cs" company="Steven Kirk">
+// Copyright 2014 MIT Licence. See licence.md for more information.
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace Perspex.Controls.Primitives.UnitTests
+{
+    using Perspex.Controls.Presenters;
+    using Perspex.Controls.Primitives;
+    using Perspex.Input;
+    using Xunit;
+
+    public class SelectingItemsControlTests
+    {
+        [Fact]
+        public void Item_IsSelected_Should_Initially_Be_False()
+        {
+            var items = new[]
+            {
+                new Item(),
+                new Item(),
+            };
+
+            var target = new Target
+            {
+                Items = items,
+            };
+
+            Assert.False(items[0].IsSelected);
+            Assert.False(items[1].IsSelected);
+        }
+
+        [Fact]
+        public void Setting_SelectedItem_Should_Set_Item_IsSelected_True()
+        {
+            var items = new[]
+            {
+                new Item(),
+                new Item(),
+            };
+
+            var target = new Target
+            {
+                Items = items,
+            };
+
+            target.Template = this.Template();
+            target.ApplyTemplate();
+            target.SelectedItem = items[1];
+
+            Assert.False(items[0].IsSelected);
+            Assert.True(items[1].IsSelected);
+        }
+
+        [Fact]
+        public void Setting_SelectedItem_Should_Set_SelectedIndex()
+        {
+            var items = new[]
+            {
+                new Item(),
+                new Item(),
+            };
+
+            var target = new Target
+            {
+                Items = items,
+            };
+
+            target.Template = this.Template();
+            target.ApplyTemplate();
+            target.SelectedItem = items[1];
+
+            Assert.Equal(1, target.SelectedIndex);
+        }
+
+        [Fact]
+        public void Setting_SelectedIndex_Should_Set_SelectedItem()
+        {
+            var items = new[]
+            {
+                new Item(),
+                new Item(),
+            };
+
+            var target = new Target
+            {
+                Items = items,
+            };
+
+            target.Template = this.Template();
+            target.ApplyTemplate();
+            target.SelectedIndex = 1;
+
+            Assert.Equal(items[1], target.SelectedItem);
+        }
+
+        [Fact]
+        public void Setting_SelectedIndex_Should_Coerce()
+        {
+            var items = new[]
+            {
+                new Item(),
+                new Item(),
+            };
+            
+            var target = new Target
+            {
+                Items = items,
+            };
+
+            target.Template = this.Template();
+            target.ApplyTemplate();
+            target.SelectedIndex = 2;
+
+            Assert.Equal(1, target.SelectedIndex);
+        }
+
+        [Fact]
+        public void PointerPressed_Event_Should_Be_Handled()
+        {
+            var target = new Target();
+
+            var e = new PointerPressEventArgs
+            {
+                RoutedEvent = InputElement.PointerPressedEvent
+            };
+
+            target.RaiseEvent(e);
+
+            Assert.True(e.Handled);
+        }
+
+        private ControlTemplate Template()
+        {
+            return ControlTemplate.Create<Target>(control =>
+                new ItemsPresenter
+                {
+                    Id = "itemsPresenter",
+                    [~ItemsPresenter.ItemsProperty] = control[~ListBox.ItemsProperty],
+                    [~ItemsPresenter.ItemsPanelProperty] = control[~ListBox.ItemsPanelProperty],
+                });
+        }
+
+        private class Target : SelectingItemsControl
+        {
+        }
+
+        private class Item : Control, ISelectable
+        {
+            public bool IsSelected { get; set; }
+        }
+    }
+}

Tests/Perspex.Controls.UnitTests/SelectingItemsControlTests.cs

@@ -1,34 +0,0 @@
-// -----------------------------------------------------------------------
-// <copyright file="SelectingItemsControlTests.cs" company="Steven Kirk">
-// Copyright 2014 MIT Licence. See licence.md for more information.
-// </copyright>
-// -----------------------------------------------------------------------
-
-namespace Perspex.Controls.UnitTests
-{
-    using Perspex.Controls.Primitives;
-    using Perspex.Input;
-    using Xunit;
-
-    public class SelectingItemsControlTests
-    {
-        [Fact]
-        public void PointerPressed_Event_Should_Be_Handled()
-        {
-            var target = new Target();
-
-            var e = new PointerPressEventArgs
-            {
-                RoutedEvent = InputElement.PointerPressedEvent
-            };
-
-            target.RaiseEvent(e);
-
-            Assert.True(e.Handled);
-        }
-
-        private class Target : SelectingItemsControl
-        {
-        }
-    }
-}