using (Transaction trAdding = dbCurrent.TransactionManager.StartTransaction())
{
LinetypeTable ltt = (LinetypeTable)trAdding.GetObject(dbCurrent.LinetypeTableId, OpenMode.ForRead);
if (!ltt.Has("ACAD_ISO02W100"))
{
dbCurrent.LoadLineTypeFile("ACAD_ISO02W100", "acadiso.lin");
}
trAdding.Commit();
}