Hi,
First get the datasouce of your dropdownlist, sort it and set the datasouce again to the dropdownlist.
Try this:
DataTable dt = (DataTable)DropDownList1.DataSource;
dt.DefaultView.Sort = "Parameter_Name ASC";
dt = dt.DefaultView.ToTable();
DropDownList1.DataSource = dt;
DropDownList1.DataTextField = "Description";
DropDownList1.DataValueField = "Code";
DropDownList1.DataBind();
--Amit