Adding conditions in service.RetrieveMultiple in c#

quotequery = new QueryExpression()
{
    Distinct = false,
    EntityName = modulename,
    ColumnSet = new ColumnSet(true),
    Criteria =
    {
        Filters = 
        {
            new FilterExpression
            {
                FilterOperator = LogicalOperator.And,
                Conditions = 
                {
                    new ConditionExpression("ownerid", ConditionOperator.Equal, userid),                                
                    new ConditionExpression(contactfield, ConditionOperator.Equal, lstcredential.Contactid.ToString())                                                  
                },
            }           
        }
    }
};
 queryentityCollection = _serviceProxy.RetrieveMultiple(quotequery).Entities;