多条件查询 没值 多条件查询 没值

public static List getAllplanFine(string startime,string
endtime,string productname,string equipment, string properson)
{

List dqt = new List();
string sql = @"select *from [Plan] p inner join [Week] w on p.planid=w.pid where 1=1";
List items = new List();
if (startime.Length > 0)
{
sql += " and startime = @startime";
items.Add(new SqlParameter("@startime", startime ));
}

        if (endtime.Length > 0)
        {
            sql += " and endtime = @endtime";
            items.Add(new SqlParameter("@endtime",  endtime ));
        }
        if (equipment.Length > 0)
        {
            sql += " and equipment= @equipment";
            items.Add(new SqlParameter("@equipment", equipment));
        }

        if (productname.Length > 0)
        {
            sql += " and productname = @productname";
            items.Add(new SqlParameter("@productname", productname));
        }
        if (properson.Length > 0)
        {
            sql += " and properson= @properson";
            items.Add(new SqlParameter("@properson", properson));
        }

        DataSet ds = SqlHelper.ExecuteDataset(SqlHelper.ConnectionString, CommandType.Text, sql, items.ToArray());
        //dataset yeyou talbes
        //datable DataRow in dt.Rows 
        if (ds.Tables.Count > 0)
        {
            DataTable dt = ds.Tables[0];
            foreach (DataRow item in dt.Rows)
            {
                Plan q = new Plan();
                q.planid = int.Parse(item["planid"].ToString());
                q.productname = item["productname"].ToString();
                q.equipment = item["equipment"].ToString();
                q.functionalmodule = item["functionalmodule"].ToString();
                q.partscode = item["partscode"].ToString();
                q.partsimage = item["partsimage"].ToString();

                                    多条件查询 没值 为空

SqlHelper.ExecuteDataset
这个本身有没有错误，在里面下断点调试下