[Solved] ASP.Net Error: Conversion failed when converting the varchar value to data type int

Conversion failed when converting the varchar value AMTXTV to data type int.

i am concating two field in dropdownlist but giving error.

SqlDataAdapter adp2 = new SqlDataAdapter("select CID,   ContNo+ ' ' + No_Of_Bales from Containerno  where delid is null", con);
DataSet ds2 = new DataSet();
adp2.Fill(ds2);
DDLContno.DataSource = ds2.Tables[0];
DDLContno.DataTextField = "ContNo";
DDLContno.DataValueField = "CID";
DDLContno.DataBind();
DDLContno.Items.Insert(0, new ListItem("Select Barcode", "0"));