this.connection.ClearParameters();
                    // ищем блокировочное слово
                    this.connection.CmdText = @"
                    select isnull(field, 'не заполнено') 
                    from RB_CONTRACT_ADDFL_STRING  
                    where 
                        ID_OBJECT = @ID_CONTRACT and id_field = 18";
                    this.connection.AddInputParameter("ID_CONTRACT", System.Data.SqlDbType.Int, contract.Id);                    
                    object[] record1 = this.connection.ExecuteReadAllRec();

if (record1.Length > 0)
{
    // ...
}

if (record1 != null && record1.Length > 0)
{
    // ...
}