/// <summary>
/// Moves the caret in the specified direction.
/// </summary>
private Boolean MoveCaretInDirection(CaretNavigationDirection direction, ModifierKeys modifiers = ModifierKeys.None)
{
var owner = TemplatedParent as Control;
var isReadOnly = (owner != null && owner.GetValue<Boolean>(TextBox.IsReadOnlyProperty));
var isReadOnlyCaretVisible = (owner != null && owner.GetValue<Boolean>(TextBox.IsReadOnlyCaretVisibleProperty));
if (isReadOnly && !isReadOnlyCaretVisible && (modifiers & ModifierKeys.Shift) != ModifierKeys.Shift)
return false;
switch (direction)
{
case CaretNavigationDirection.Left:
MoveCaretLeft();
break;
case CaretNavigationDirection.Right:
MoveCaretRight();
break;
case CaretNavigationDirection.Up:
MoveCaretUp();
break;
case CaretNavigationDirection.Down:
MoveCaretDown();
break;
case CaretNavigationDirection.Home:
MoveCaretToHome((modifiers & ModifierKeys.Control) == ModifierKeys.Control);
break;
case CaretNavigationDirection.End:
MoveCaretToEnd((modifiers & ModifierKeys.Control) == ModifierKeys.Control);
break;
case CaretNavigationDirection.PageUp:
MoveCaretPageUp();
break;
case CaretNavigationDirection.PageDown:
MoveCaretPageDown();
break;
}
return true;
}
/// <summary>
/// Handles movement events which affect the selection.
/// </summary>
/// <param name="movementAllowed">A value indicating whether the user's desired movement is allowed.</param>
/// <param name="movementDirection">A <see cref="CaretNavigationDirection"/> value specifying which direction the selection is moving.</param>
/// <returns><see langword="true"/> if the movement was handled; otherwise, <see langword="false"/>.</returns>
private Boolean HandleSelectionMovement(Boolean movementAllowed, CaretNavigationDirection movementDirection)
{
var selecting = (Keyboard.Modifiers & ModifierKeys.Shift) == ModifierKeys.Shift;
if (selecting)
{
if (selectionPosition == null)
selectionPosition = caretPosition;
return !movementAllowed;
}
else
{
if (selectionPosition == null)
return !movementAllowed;
var newCaretPosition =
(movementDirection == CaretNavigationDirection.Left) ? SelectionStart :
(movementDirection == CaretNavigationDirection.Right) ? SelectionStart + SelectionLength : (Int32?)null;
selectionPosition = null;
if (newCaretPosition.HasValue)
{
caretBlinkTimer = 0;
caretPosition = newCaretPosition.Value;
UpdateCaret();
UpdateSelection();
return true;
}
return !movementAllowed;
}
}
