Implemented Ctrl+Backspace and Ctrl+Delete for TextBox.

Fixes #609

src/Avalonia.Controls/TextBox.cs

@@ -304,7 +304,7 @@ namespace Avalonia.Controls
                     break;
 
                 case Key.X:
-                    if(modifiers == InputModifiers.Control)
+                    if (modifiers == InputModifiers.Control)
                     {
                         Copy();
                         DeleteSelection();
@@ -360,6 +360,11 @@ namespace Avalonia.Controls
                     break;
 
                 case Key.Back:
+                    if (modifiers == InputModifiers.Control && SelectionStart == SelectionEnd)
+                    {
+                        SetSelectionForControlBackspace(modifiers);
+                    }
+
                     if (!DeleteSelection() && CaretIndex > 0)
                     {
                         CaretIndex -= DeleteCharacter(CaretIndex - 1);
@@ -368,6 +373,11 @@ namespace Avalonia.Controls
                     break;
 
                 case Key.Delete:
+                    if (modifiers == InputModifiers.Control && SelectionStart == SelectionEnd)
+                    {
+                        SetSelectionForControlDelete(modifiers);
+                    }
+
                     if (!DeleteSelection() && caretIndex < text.Length)
                     {
                         DeleteCharacter(CaretIndex);
@@ -700,6 +710,26 @@ namespace Avalonia.Controls
             return i;
         }
 
+        private void SetSelectionForControlBackspace(InputModifiers modifiers)
+        {
+            SelectionStart = CaretIndex;
+            MoveHorizontal(-1, modifiers);
+            SelectionEnd = CaretIndex;
+        }
+
+        private void SetSelectionForControlDelete(InputModifiers modifiers)
+        {
+            SelectionStart = CaretIndex;
+            MoveHorizontal(1, modifiers);
+            SelectionEnd = CaretIndex;
+
+            string selection = GetSelection();
+            if (selection != " " && selection.EndsWith(" "))
+            {
+                SelectionEnd = CaretIndex - 1;
+            }
+        }
+
         UndoRedoState UndoRedoHelper<UndoRedoState>.IUndoRedoHost.UndoRedoState
         {
             get { return new UndoRedoState(Text, CaretIndex); }

src/Avalonia.Controls/Utils/StringUtils.cs

@@ -190,6 +190,12 @@ namespace Avalonia.Controls.Utils
             {
                 i = cursor;
 
+                // skip any whitespace before the word
+                while (i < cr && char.IsWhiteSpace(text[i]))
+                {
+                    i++;
+                }
+
                 // skip to the end of the current word
                 while (i < cr && !char.IsWhiteSpace(text[i]))
                 {

tests/Avalonia.Controls.UnitTests/TextBoxTests.cs

@@ -2,6 +2,10 @@
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
 using Avalonia.Data;
+using Avalonia.Input;
+using Avalonia.Platform;
+using Avalonia.UnitTests;
+using Moq;
 using Xunit;
 
 namespace Avalonia.Controls.UnitTests
@@ -15,5 +19,95 @@ namespace Avalonia.Controls.UnitTests
                 BindingMode.TwoWay,
                 TextBox.TextProperty.GetMetadata(typeof(TextBox)).DefaultBindingMode);
         }
+
+        [Fact]
+        public void Control_Backspace_Should_Remove_The_Word_Before_The_Caret_If_There_Is_No_Selection()
+        {
+            AvaloniaLocator.CurrentMutable
+                .Bind<IPlatformThreadingInterface>()
+                .ToConstant(TestServices.MockThreadingInterface.ThreadingInterface);
+
+            TextBox textBox = new TextBox
+            {
+                Text = "First Second Third Fourth",
+                CaretIndex = 5
+            };
+
+            // (First| Second Third Fourth)
+            RaiseKeyEvent(textBox, Key.Back, InputModifiers.Control);
+            Assert.Equal(" Second Third Fourth", textBox.Text);
+
+            // ( Second |Third Fourth)
+            textBox.CaretIndex = 8;
+            RaiseKeyEvent(textBox, Key.Back, InputModifiers.Control);
+            Assert.Equal(" Third Fourth", textBox.Text);
+
+            // ( Thi|rd Fourth)
+            textBox.CaretIndex = 4;
+            RaiseKeyEvent(textBox, Key.Back, InputModifiers.Control);
+            Assert.Equal(" rd Fourth", textBox.Text);
+
+            // ( rd F[ou]rth)
+            textBox.SelectionStart = 5;
+            textBox.SelectionEnd = 7;
+
+            RaiseKeyEvent(textBox, Key.Back, InputModifiers.Control);
+            Assert.Equal(" rd Frth", textBox.Text);
+
+            // ( |rd Frth)
+            textBox.CaretIndex = 1;
+            RaiseKeyEvent(textBox, Key.Back, InputModifiers.Control);
+            Assert.Equal("rd Frth", textBox.Text);
+        }
+
+        [Fact]
+        public void Control_Delete_Should_Remove_The_Word_After_The_Caret_If_There_Is_No_Selection()
+        {
+            AvaloniaLocator.CurrentMutable
+                .Bind<IPlatformThreadingInterface>()
+                .ToConstant(TestServices.MockThreadingInterface.ThreadingInterface);
+
+            TextBox textBox = new TextBox
+            {
+                Text = "First Second Third Fourth",
+                CaretIndex = 19
+            };
+
+            // (First Second Third |Fourth)
+            RaiseKeyEvent(textBox, Key.Delete, InputModifiers.Control);
+            Assert.Equal("First Second Third ", textBox.Text);
+
+            // (First Second| Third )
+            textBox.CaretIndex = 12;
+            RaiseKeyEvent(textBox, Key.Delete, InputModifiers.Control);
+            Assert.Equal("First Second ", textBox.Text);
+
+            // (First Sec|ond )
+            textBox.CaretIndex = 9;
+            RaiseKeyEvent(textBox, Key.Delete, InputModifiers.Control);
+            Assert.Equal("First Sec ", textBox.Text);
+
+            // (Fi[rs]t Sec )
+            textBox.SelectionStart = 2;
+            textBox.SelectionEnd = 4;
+
+            RaiseKeyEvent(textBox, Key.Delete, InputModifiers.Control);
+            Assert.Equal("Fit Sec ", textBox.Text);
+
+            // (Fit Sec| )
+            textBox.CaretIndex = 7;
+            RaiseKeyEvent(textBox, Key.Delete, InputModifiers.Control);
+            Assert.Equal("Fit Sec", textBox.Text);
+        }
+
+        private void RaiseKeyEvent(TextBox textBox, Key key, InputModifiers inputModifiers)
+        {
+            textBox.RaiseEvent(new KeyEventArgs
+            {
+                RoutedEvent = InputElement.KeyDownEvent,
+                Modifiers = inputModifiers,
+                Key = key
+            });
+        }
     }
 }