Populating a dropdown list from the database c# aspx - asp.net

Question

I am struggling a bit to populate my dropdown list, can anybody tell me where I am going wrong?
ASPX CODE it keeps looping after getting the connection string - back into the connection string method.
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
BindDropDownList();
}
}
private string GetConnectionString()
{
using (DataManager dmgr = new DataManager())
{
dmgr.Connect(ConfigurationManager.AppSettings["ProductionKey"]);
return BindDropDownList();
}
}
public string BindDropDownList()
{
DataTable dt = new DataTable();
SqlConnection connection = new SqlConnection(GetConnectionString());
try
{
connection.Open();
string sqlStatement = "SELECT * FROM Itemseriesmaster";
SqlCommand sqlCmd = new SqlCommand(sqlStatement, connection);
SqlDataAdapter sqlDa = new SqlDataAdapter(sqlCmd);
sqlDa.Fill(dt);
if (dt.Rows.Count > 0)
{
DropDownList1.DataSource = dt;
DropDownList1.DataTextField = "Description"; // the items to be displayed in the list items
DropDownList1.DataValueField = "ID"; // the id of the items displayed
DropDownList1.DataBind();
}
}
catch (SqlException ex)
{
string msg = "Fetch Error:";
msg += ex.Message;
throw new Exception(msg);
}
finally
{
connection.Close();
}
return AppRelativeTemplateSourceDirectory;
}
DataManager Code - where the code calls into
public DataSet ItemSeriesMaster(int id, string description)
{
object[] args = new object[2] { id, description };
return CallSp(MethodBase.GetCurrentMethod(), args) as DataSet; // i know this is not an sp call.. just testing
}
}
}
I am trying to go to my database and bring out the list.