<asp:boundfield datafield="ID" headertext="ID" headerstyle-wrap="false" Sortexpression="ID"/>

if (e.Row.RowType == DataControlRowType.Header)
            {
                string ID = ViewState["ID"].ToString();
                DataTable dtColumnNames = GetColumns(ID);
                string[] strColumns = dtColumnText.Rows.OfType<DataRow>().Select(k => k[1].ToString()).ToArray();
                for (int i = 0; i < strColumns.Length; i++)
                {
                    e.Row.Cells[i].Text = strColumns[i];
                }
            }