we load the drop down of another combo then give me error

Question

these are store procedure

 

alter procedure GetCompanyForSell

as

begin

select c.Name, c.companyid from Tbl_Product as p join Tbl_Company as c on c.companyid=p.company_id

where p.Quantity>0

end

end

when load then give error

Additional information: Input string was not in a correct format.Couldn't store in ddd Column. Expected type is Int32. 

the code is given below

 

public void GetCompany()

{

DataRow dr;

List prm = new List();

DataSet ds = rp.GetDS("GetCompanyForSell", prm);

DataTable dt = ds.Tables[0];

dr = dt.NewRow();

dr.ItemArray = new object[2] { 0, "?????? ????" };

dt.Rows.InsertAt(dr, 0);

cmb_company.DataSource = dt;

cmb_company.DisplayMember = "Name";

cmb_company.ValueMember = "ddd";

}

please solve the problems