Actually I want to bind a single field from one table into DropDownList

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
  {
      int intReference = int.Parse(ddlCompany.SelectedValue.ToString());
// call the function where u will interact with database .
      fnShowDetails(intReference);
  }

protected void fnShowDetails(int intReference)
  {
      DataSet dsGetTechAcq = new DataSet();
      dsGetTechAcq = objExpenditure.fnGetTechAcq(intReference);
      gvHardware.DataSource = dsGetTechAcq.Tables[0];
      gvHardware.DataBind();
}