public string GetIdentityClientName(int clientId) { if (clientId == 0 | clientId == -1) { return("Ошибка заполнения клиента."); } var identityClientName = SqlQueryBuilder.SelectIdentityClientName(clientId, DBConnection); var result = identityClientName.ExecuteScalar(); if (result != null) { return(result.ToString()); } else { return(null); } }