static EditingCommandHandler()
        {
            CommandBindings.Add(new CommandBinding(ApplicationCommands.Delete, OnDelete(ApplicationCommands.NotACommand), CanDelete));
            AddBinding(EditingCommands.Delete, ModifierKeys.None, Key.Delete, OnDelete(EditingCommands.SelectRightByCharacter));
            AddBinding(EditingCommands.DeleteNextWord, ModifierKeys.Control, Key.Delete, OnDelete(EditingCommands.SelectRightByWord));
            AddBinding(EditingCommands.Backspace, ModifierKeys.None, Key.Back, OnDelete(EditingCommands.SelectLeftByCharacter));
            InputBindings.Add(TextAreaDefaultInputHandler.CreateFrozenKeyBinding(EditingCommands.Backspace, ModifierKeys.Shift, Key.Back));             // make Shift-Backspace do the same as plain backspace
            AddBinding(EditingCommands.DeletePreviousWord, ModifierKeys.Control, Key.Back, OnDelete(EditingCommands.SelectLeftByWord));
            AddBinding(EditingCommands.EnterParagraphBreak, ModifierKeys.None, Key.Enter, OnEnter);
            AddBinding(EditingCommands.EnterLineBreak, ModifierKeys.Shift, Key.Enter, OnEnter);
            AddBinding(EditingCommands.TabForward, ModifierKeys.None, Key.Tab, OnTab);
            AddBinding(EditingCommands.TabBackward, ModifierKeys.Shift, Key.Tab, OnShiftTab);

            CommandBindings.Add(new CommandBinding(ApplicationCommands.Copy, OnCopy, CanCutOrCopy));
            CommandBindings.Add(new CommandBinding(ApplicationCommands.Cut, OnCut, CanCutOrCopy));
            CommandBindings.Add(new CommandBinding(ApplicationCommands.Paste, OnPaste, CanPaste));

            CommandBindings.Add(new CommandBinding(AvalonEditCommands.DeleteLine, OnDeleteLine));

            CommandBindings.Add(new CommandBinding(AvalonEditCommands.RemoveLeadingWhitespace, OnRemoveLeadingWhitespace));
            CommandBindings.Add(new CommandBinding(AvalonEditCommands.RemoveTrailingWhitespace, OnRemoveTrailingWhitespace));
            CommandBindings.Add(new CommandBinding(AvalonEditCommands.ConvertToUppercase, OnConvertToUpperCase));
            CommandBindings.Add(new CommandBinding(AvalonEditCommands.ConvertToLowercase, OnConvertToLowerCase));
            CommandBindings.Add(new CommandBinding(AvalonEditCommands.ConvertToTitleCase, OnConvertToTitleCase));
            CommandBindings.Add(new CommandBinding(AvalonEditCommands.InvertCase, OnInvertCase));
            CommandBindings.Add(new CommandBinding(AvalonEditCommands.ConvertTabsToSpaces, OnConvertTabsToSpaces));
            CommandBindings.Add(new CommandBinding(AvalonEditCommands.ConvertSpacesToTabs, OnConvertSpacesToTabs));
            CommandBindings.Add(new CommandBinding(AvalonEditCommands.ConvertLeadingTabsToSpaces, OnConvertLeadingTabsToSpaces));
            CommandBindings.Add(new CommandBinding(AvalonEditCommands.ConvertLeadingSpacesToTabs, OnConvertLeadingSpacesToTabs));
            CommandBindings.Add(new CommandBinding(AvalonEditCommands.IndentSelection, OnIndentSelection));

            TextAreaDefaultInputHandler.WorkaroundWPFMemoryLeak(InputBindings);
        }
        static CaretNavigationCommandHandler()
        {
            const ModifierKeys None  = ModifierKeys.None;
            const ModifierKeys Ctrl  = ModifierKeys.Control;
            const ModifierKeys Shift = ModifierKeys.Shift;
            const ModifierKeys Alt   = ModifierKeys.Alt;

            AddBinding(EditingCommands.MoveLeftByCharacter, None, Key.Left, OnMoveCaret(CaretMovementType.CharLeft));
            AddBinding(EditingCommands.SelectLeftByCharacter, Shift, Key.Left, OnMoveCaretExtendSelection(CaretMovementType.CharLeft));
            AddBinding(RectangleSelection.BoxSelectLeftByCharacter, Alt | Shift, Key.Left, OnMoveCaretBoxSelection(CaretMovementType.CharLeft));
            AddBinding(EditingCommands.MoveRightByCharacter, None, Key.Right, OnMoveCaret(CaretMovementType.CharRight));
            AddBinding(EditingCommands.SelectRightByCharacter, Shift, Key.Right, OnMoveCaretExtendSelection(CaretMovementType.CharRight));
            AddBinding(RectangleSelection.BoxSelectRightByCharacter, Alt | Shift, Key.Right, OnMoveCaretBoxSelection(CaretMovementType.CharRight));

            AddBinding(EditingCommands.MoveLeftByWord, Ctrl, Key.Left, OnMoveCaret(CaretMovementType.WordLeft));
            AddBinding(EditingCommands.SelectLeftByWord, Ctrl | Shift, Key.Left, OnMoveCaretExtendSelection(CaretMovementType.WordLeft));
            AddBinding(RectangleSelection.BoxSelectLeftByWord, Ctrl | Alt | Shift, Key.Left, OnMoveCaretBoxSelection(CaretMovementType.WordLeft));
            AddBinding(EditingCommands.MoveRightByWord, Ctrl, Key.Right, OnMoveCaret(CaretMovementType.WordRight));
            AddBinding(EditingCommands.SelectRightByWord, Ctrl | Shift, Key.Right, OnMoveCaretExtendSelection(CaretMovementType.WordRight));
            AddBinding(RectangleSelection.BoxSelectRightByWord, Ctrl | Alt | Shift, Key.Right, OnMoveCaretBoxSelection(CaretMovementType.WordRight));

            AddBinding(EditingCommands.MoveUpByLine, None, Key.Up, OnMoveCaret(CaretMovementType.LineUp));
            AddBinding(EditingCommands.SelectUpByLine, Shift, Key.Up, OnMoveCaretExtendSelection(CaretMovementType.LineUp));
            AddBinding(RectangleSelection.BoxSelectUpByLine, Alt | Shift, Key.Up, OnMoveCaretBoxSelection(CaretMovementType.LineUp));
            AddBinding(EditingCommands.MoveDownByLine, None, Key.Down, OnMoveCaret(CaretMovementType.LineDown));
            AddBinding(EditingCommands.SelectDownByLine, Shift, Key.Down, OnMoveCaretExtendSelection(CaretMovementType.LineDown));
            AddBinding(RectangleSelection.BoxSelectDownByLine, Alt | Shift, Key.Down, OnMoveCaretBoxSelection(CaretMovementType.LineDown));

            AddBinding(EditingCommands.MoveDownByPage, None, Key.PageDown, OnMoveCaret(CaretMovementType.PageDown));
            AddBinding(EditingCommands.SelectDownByPage, Shift, Key.PageDown, OnMoveCaretExtendSelection(CaretMovementType.PageDown));
            AddBinding(EditingCommands.MoveUpByPage, None, Key.PageUp, OnMoveCaret(CaretMovementType.PageUp));
            AddBinding(EditingCommands.SelectUpByPage, Shift, Key.PageUp, OnMoveCaretExtendSelection(CaretMovementType.PageUp));

            AddBinding(EditingCommands.MoveToLineStart, None, Key.Home, OnMoveCaret(CaretMovementType.LineStart));
            AddBinding(EditingCommands.SelectToLineStart, Shift, Key.Home, OnMoveCaretExtendSelection(CaretMovementType.LineStart));
            AddBinding(RectangleSelection.BoxSelectToLineStart, Alt | Shift, Key.Home, OnMoveCaretBoxSelection(CaretMovementType.LineStart));
            AddBinding(EditingCommands.MoveToLineEnd, None, Key.End, OnMoveCaret(CaretMovementType.LineEnd));
            AddBinding(EditingCommands.SelectToLineEnd, Shift, Key.End, OnMoveCaretExtendSelection(CaretMovementType.LineEnd));
            AddBinding(RectangleSelection.BoxSelectToLineEnd, Alt | Shift, Key.End, OnMoveCaretBoxSelection(CaretMovementType.LineEnd));

            AddBinding(EditingCommands.MoveToDocumentStart, Ctrl, Key.Home, OnMoveCaret(CaretMovementType.DocumentStart));
            AddBinding(EditingCommands.SelectToDocumentStart, Ctrl | Shift, Key.Home, OnMoveCaretExtendSelection(CaretMovementType.DocumentStart));
            AddBinding(EditingCommands.MoveToDocumentEnd, Ctrl, Key.End, OnMoveCaret(CaretMovementType.DocumentEnd));
            AddBinding(EditingCommands.SelectToDocumentEnd, Ctrl | Shift, Key.End, OnMoveCaretExtendSelection(CaretMovementType.DocumentEnd));

            CommandBindings.Add(new CommandBinding(ApplicationCommands.SelectAll, OnSelectAll));

            TextAreaDefaultInputHandler.WorkaroundWPFMemoryLeak(InputBindings);
        }
 static void AddBinding(ICommand command, ModifierKeys modifiers, Key key, ExecutedRoutedEventHandler handler)
 {
     CommandBindings.Add(new CommandBinding(command, handler));
     InputBindings.Add(TextAreaDefaultInputHandler.CreateFrozenKeyBinding(command, modifiers, key));
 }