Convert HTML string to PDF and send as email attachment using C# in ASP.Net

Here's the corrected code

Namespaces

using System.IO;
using System.Net.Mail;
using iTextSharp.text;
using iTextSharp.text.pdf;
using iTextSharp.text.html.simpleparser;
using System.Data;
using System.Text;

Code

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        DataTable dt = new DataTable();
        dt.Columns.AddRange(new DataColumn[3] {
		new DataColumn("Id"),
		new DataColumn("Name"),
		new DataColumn("Country")});
        dt.Rows.Add(1, "John Hammond", "United States");
        dt.Rows.Add(2, "Mudassar Khan", "India");
        dt.Rows.Add(3, "Suzanne Mathews", "France");
        dt.Rows.Add(4, "Robert Schidner", "Russia");
        ExportToPDF(dt);
    }
}

private void ExportToPDF(DataTable dt)
{
    using (StringWriter sw = new StringWriter())
    {
        using (HtmlTextWriter hw = new HtmlTextWriter(sw))
        {

            StringBuilder sb = new StringBuilder();
            sb.Append("<table width='100%' cellspacing='0' cellpadding='2'>");
            sb.Append("<tr><td align='center' style='background-color: #18B5F0' colspan = '2'><b>Order Sheet</b></td></tr>");
            sb.Append("<tr><td colspan = '2'></td></tr>");
            sb.Append("<tr><td><b>Order No:</b> 100</td><td><b>Date: </b>" + DateTime.Now + " </td></tr>");
            sb.Append("<tr><td><b>From :</b> " + "Company Name" + " </td><td><b>To: </b>" + " Some Company " + " </td></tr>");
            sb.Append("</table>");

            sb.Append("<table border = '1'>");
            sb.Append("<tr>");
            foreach (DataColumn column in dt.Columns)
            {
                sb.Append("<th>");
                sb.Append(column.ColumnName);
                sb.Append("</th>");
            }
            sb.Append("</tr>");
            foreach (DataRow row in dt.Rows)
            {
                sb.Append("<tr>");
                foreach (DataColumn column in dt.Columns)
                {
                    sb.Append("<td>");
                    sb.Append(row[column]);
                    sb.Append("</td>");
                }
                sb.Append("</tr>");
            }
            sb.Append("</table>");

            StringReader sr = new StringReader(sb.ToString());

            Document pdfDoc = new Document(PageSize.A4, 10f, 10f, 10f, 0f);
            HTMLWorker htmlparser = new HTMLWorker(pdfDoc);
            using (MemoryStream memoryStream = new MemoryStream())
            {
                PdfWriter writer = PdfWriter.GetInstance(pdfDoc, memoryStream);
                pdfDoc.Open();
                htmlparser.Parse(sr);
                pdfDoc.Close();
                byte[] bytes = memoryStream.ToArray();
                memoryStream.Close();

                MailMessage mm = new MailMessage("sender@gmail.com", "receiver@gmail.com");
                mm.Subject = "GridView Exported PDF";
                mm.Body = "GridView Exported PDF Attachment";
                mm.Attachments.Add(new Attachment(new MemoryStream(bytes), "GridViewPDF.pdf"));
                mm.IsBodyHtml = true;
                SmtpClient smtp = new SmtpClient();
                smtp.Host = "smtp.gmail.com";
                smtp.EnableSsl = true;
                System.Net.NetworkCredential NetworkCred = new System.Net.NetworkCredential();
                NetworkCred.UserName = "sender@gmail.com";
                NetworkCred.Password = "password";
                smtp.UseDefaultCredentials = true;
                smtp.Credentials = NetworkCred;
                smtp.Port = 587;
                smtp.Send(mm);
            }
        }
    }
}

Screenshot