UnitResult Redo()
{
if (globallyRedoableUnits.Count < 1)
{
throw new InvalidOperationException("No unit to redo."); /* TODO: Make localizable resource. */
}
var unit = globallyRedoableUnits.Pop();
var eventArgs = new CancellableUndoServiceEventArgs(unit);
OnRedoing(eventArgs);
if (eventArgs.Cancel)
{
globallyRedoableUnits.AddLast(unit);
return(UnitResult.Cancelled);
}
var internalUnit = (IInternalUnit)unit;
globallyRepeatableUnits.AddLast(internalUnit);
globallyUndoableUnits.AddLast(unit);
var result = internalUnit.PerformUnit(internalUnit.Argument, UnitMode.Redo);
TrimIfRequired();
OnRedone(new UndoServiceEventArgs(unit));
return(result);
}
UnitResult Undo()
{
if (globallyRepeatableUnits.Count < 1)
{
throw new InvalidOperationException("No unit to undo.");
}
IUndoableUnit undoableUnit = globallyUndoableUnits.Pop();
IInternalUnit repeatableUnit = globallyRepeatableUnits.Pop();
var eventArgs = new CancellableUndoServiceEventArgs(undoableUnit);
OnUndoing(eventArgs);
if (eventArgs.Cancel)
{
globallyUndoableUnits.AddLast(undoableUnit);
globallyRepeatableUnits.AddLast(repeatableUnit);
return(UnitResult.Cancelled);
}
globallyRedoableUnits.AddLast(undoableUnit);
UnitResult result = undoableUnit.Undo();
OnUndone(new UndoServiceEventArgs(undoableUnit));
return(result);
}