/// <summary>
/// Navigates backward in the selection history.
/// </summary>
public void NavigateBackward()
{
// Should hardly happen, but let's ignore this action if we're still terminating a selection
if (currentTransaction != null)
{
return;
}
var initialState = CurrentState;
while (stack.CanRollback && (initialState.Equals(CurrentState) || !CurrentState.HasValidSelection()))
{
stack.Rollback();
// Skip transactions that don't have effect anymore
}
}
public void Undo()
{
if (CanUndo)
{
UndoRedoInProgress = true;
undoRedoCompletion = new TaskCompletionSource <int>();
try
{
stack.Rollback();
}
finally
{
undoRedoCompletion.SetResult(0);
undoRedoCompletion = null;
UndoRedoInProgress = false;
}
}
}
public void Undo()
{
UndoRedoInProgress = true;
stack.Rollback();
UndoRedoInProgress = false;
}