Insert data in hierarchial radgrid

See more:

C#

SQL

hello,

I want to insert data into hierarchial radgrid...ie when is exapnd button i should be able to see the data after expansion...

im getting no display in child radgrid..in the child column..
can anyone tell me how to proceed???This the code im using..and i want this without using datasource.
Thank You

protected void RadGrid_Details_DetailTableDataBind(object sender, GridDetailTableDataBindEventArgs e)
        {
            var Value= e.DetailTableView.ParentItem;
               string ID = Value.GetDataKeyValue("ID").ToString();
               e.DetailTableView.DataSource = GetDataTable("SELECT * FROM databsename WHERE ID = '" + ID + "'");
                   
        }

        public DataTable GetDataTable(string query)
        {
            SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["constr"].ToString());

            SqlDataAdapter da = new SqlDataAdapter("select * from databasename ", con);
            DataSet ds = new DataSet();
            da.Fill(ds, "databasename");
            RadGrid_Details.DataSource = ds;

            DataTable myDataTable = new DataTable();

            con.Open();
            
                da.Fill(myDataTable);
         
          
            return myDataTable;
        }