private bool IsСapacityHDD(Collection <ListBoxObject> collection, Case @case, string problem_report) { bool isValid = false; Collection <HDD> hdd_collection = new Collection <HDD>(); foreach (ListBoxObject lbo in collection.Where(i => i.Item.GetTypeValue() == "hdd")) { hdd_collection.Add(lbo.IObject as HDD); } if (@case.CheckСapacity(hdd_collection)) { isValid = true; } else { ProblemReport(problem_report); } return(isValid); }