private bool ValidateAll() { bool supplierInvalid = false; if (BindingSourceSupplierRegion.List.Count > 0) { supplierInvalid = BindingSourceSupplierRegion.List.Cast <SupplierRegion>().Any(b => !b.Validate()); } if (!_selectedRecord.Validate() || supplierInvalid) { ShowMainControlErrors(); DisplayHelper.DisplayWarning(this, "Errors were found. Please resolve them and try again."); return(false); } else { ErrorProvider.Clear(); return(true); } }