Download .pdf from SQL Server database

Dictionary<string, Guid> downloads = GetDownloadList();
StringBuilder sb = new StringBuilder();
foreach (KeyValuePair<string, Guid> file in downloads)
    {
    sb.Append("<tr><td>");
    sb.Append(file.Key);
    sb.Append("</td></tr>");
    HtmlTableRow row = new HtmlTableRow();
    HtmlTableCell cell = new HtmlTableCell();
    cell.InnerHtml = "<a href=\"wm5ftdl.aspx?file=" + file.Value + "\" target=\"_blank\">" + file.Key + "</a>";
    row.Cells.Add(cell);
    tbDownloads.Rows.Add(row);
    }

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="wm5ftdl.aspx.cs" Inherits="wm5ftdl" %>

<%
    // Send a download file to the client given the filename.
    string guid = Request.QueryString["file"];
    string fileName = "ERROR";
    byte[] data = new byte[] { 0, 0, 0, 0 };
    string strCon = System.Web.Configuration.WebConfigurationManager.ConnectionStrings["DownloadDatabase"].ConnectionString;
    using (System.Data.SqlClient.SqlConnection con = new System.Data.SqlClient.SqlConnection(strCon))
        {
        con.Open();
        string strcmd = "SELECT [iD] ,cn.[fileName],[description] ,[dataContent] ,[version] " +
                        "FROM dlContent cn " +

                        "WHERE cn.iD=@ID";
        using (System.Data.SqlClient.SqlCommand cmd = new System.Data.SqlClient.SqlCommand(strcmd, con))
            {
            cmd.Parameters.AddWithValue("@ID", guid);
            using (System.Data.SqlClient.SqlDataReader r = cmd.ExecuteReader())
                {
                if (r.Read())
                    {
                    fileName = (string) r["filename"];
                    data = (byte[]) r["dataContent"];
                    }
                }
            }
        }
    Response.Clear();
    Response.AddHeader("Cache-Control", "no-cache, must-revalidate, post-check=0, pre-check=0");
    Response.AddHeader("Pragma", "no-cache");
    Response.AddHeader("Content-Description", "File Download");
    Response.AddHeader("Content-Type", "application/force-download");
    Response.AddHeader("Content-Transfer-Encoding", "binary\n");
    Response.AddHeader("content-disposition", "attachment;filename=" + fileName);
    Response.BinaryWrite(data);
    //Response.WriteFile("wm5ftdata/" + fileName);
    Response.End();
%>