public override HistoryMemento OnExecute(IHistoryWorkspace historyWorkspace)
{
if (historyWorkspace.Selection.IsEmpty)
{
return(null);
}
else
{
SelectionHistoryMemento sha = new SelectionHistoryMemento(
StaticName,
StaticImage,
historyWorkspace);
PdnRegion selectedRegion = historyWorkspace.Selection.CreateRegion();
selectedRegion.Xor(historyWorkspace.Document.Bounds);
PdnGraphicsPath invertedSelection = PdnGraphicsPath.FromRegion(selectedRegion);
selectedRegion.Dispose();
EnterCriticalRegion();
historyWorkspace.Selection.PerformChanging();
historyWorkspace.Selection.Reset();
historyWorkspace.Selection.SetContinuation(invertedSelection, CombineMode.Xor, true);
historyWorkspace.Selection.CommitContinuation();
historyWorkspace.Selection.PerformChanged();
return(sha);
}
}