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);
}
UnitResult PerformUnit <T>(UndoableUnitBase <T> unit, T argument)
{
var eventArgs = new CancellableUndoServiceEventArgs(unit);
OnExecuting(eventArgs);
if (eventArgs.Cancel)
{
return(UnitResult.Cancelled);
}
globallyRedoableUnits.Clear();
globallyRepeatableUnits.AddLast(unit);
globallyUndoableUnits.AddLast(unit);
UnitResult result = unit.PerformUnit(argument, UnitMode.FirstTime);
TrimIfRequired();
OnExecuted(new UndoServiceEventArgs(unit));
return(result);
}
