<asp:TextBox ID="txtAuto" runat="server"></asp:TextBox>
     <div id="Panel">
                            </div>
          <asp:AutoCompleteExtender ID="AutoCompleteExtender1" runat="server" CompletionInterval="0"
                                CompletionListElementID="Panel" CompletionSetCount="12" EnableCaching="true"
                                MinimumPrefixLength="1" ServiceMethod="GetProductList" 
                                ShowOnlyCurrentWordInCompletionListItem="true" TargetControlID="txtAuto"
                               >
                            </asp:AutoCompleteExtender>
                            <%-- <asp:AutoCompleteExtender ID="AutoCompleteExtender1" runat="server" TargetControlID="txtAuto"
MinimumPrefixLength="1" EnableCaching="true" CompletionSetCount="1" CompletionInterval="1000" ServiceMethod="GetProductList" >
</asp:AutoCompleteExtender>--%>
                            </br>
                            <asp:Button ID="btnSubmitt" runat="server" Text="Submitt"  OnClick="btnSubmitt_Click"  />
                            </br>
                           
                            <asp:Label ID="lblLocation" runat="server"></asp:Label></br>
                            <asp:Label ID="lblLevel" runat="server"></asp:Label>
    </div>

........................................................

 [System.Web.Script.Services.ScriptMethod()]
        [System.Web.Services.WebMethod]
        public static string[] GetProductList(string prefixText)
        {

            string connString = "";

            string path = @"C:\Test\Company.xls";
            //Connection String to Excel Workboo
            //if (strFileType.Trim() == ".xls")
            //{
           // connString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + path + ";Extended Properties=\"Excel 8.0;HDR=Yes;IMEX=2\"";

            connString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + path + ";Extended Properties=\"Excel 12.0;HDR=Yes;IMEX=2\"";
            //}
            //else if (strFileType.Trim() == ".xlsx")
            //{
            //    connString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + path + ";Extended Properties=\"Excel 12.0;HDR=Yes;IMEX=2\"";
            //}
         //  string query = "SELECT [Company] FROM [Sheet1$] where Company like '" + prefixText + "'";
           string query = "SELECT [Company] FROM [Sheet1$] where Company like '" + prefixText + "'+'%'";

            OleDbConnection conn = new OleDbConnection(connString);
            if (conn.State == ConnectionState.Closed)
            {
                conn.Open();
            }
            else
            {

            }
            OleDbCommand cmd = new OleDbCommand(query, conn);
            OleDbDataAdapter da = new OleDbDataAdapter();
            da.SelectCommand = cmd;
            DataSet ds = new DataSet();
            da.Fill(ds);

                                  
            DataTable dt = ds.Tables[0];

            List<string> txtProductName = new List<string>();
            String dbValues;

            foreach (DataRow row in dt.Rows)
            {

                dbValues = row["Company"].ToString();
                dbValues = dbValues.ToLower();
                txtProductName.Add(dbValues);
            }

            return txtProductName.ToArray();
        }

        protected void btnSubmitt_Click(object sender, System.EventArgs e)
        {
            string connString = "";

            string path = @"C:\Test\Company.xls";
            //Connection String to Excel Workboo
            //if (strFileType.Trim() == ".xls")
            //{
            // connString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + path + ";Extended Properties=\"Excel 8.0;HDR=Yes;IMEX=2\"";

            connString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + path + ";Extended Properties=\"Excel 12.0;HDR=Yes;IMEX=2\"";
            //}
            //else if (strFileType.Trim() == ".xlsx")
            //{
            //    connString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + path + ";Extended Properties=\"Excel 12.0;HDR=Yes;IMEX=2\"";
            //}
            //  string query = "SELECT [Company] FROM [Sheet1$] where Company like '" + prefixText + "'";
            string query = "SELECT [Location],[Level] FROM [Sheet1$] where Company = '" + txtAuto.Text.Trim() + "'";

            OleDbConnection conn = new OleDbConnection(connString);
            if (conn.State == ConnectionState.Closed)
            {
                conn.Open();
            }
            else
            {

            }
            OleDbCommand cmd = new OleDbCommand(query, conn);
            OleDbDataAdapter da = new OleDbDataAdapter();
            da.SelectCommand = cmd;
            DataSet ds = new DataSet();
            da.Fill(ds);
            if (ds.Tables[0].Rows.Count > 0)
            {

                lblLocation.Text = Convert.ToString(ds.Tables[0].Rows[0]["Location"]);
                lblLevel.Text = Convert.ToString(ds.Tables[0].Rows[0]["Level"]);
            }

        }