Print ( Export ) TextBox Contents as PDF using iTextSharp in ASP.Net

hello, I want to print  one TexBox (TextMode = "MultiLine") to  pdf with ITEXTSHARP !!

My problem is that when I print the textbox contained ,he displays contained in html forma

Here is my code printing

PdfPTable TblB = new PdfPTable(1);
        float[] Awidthss = new float[] { 4f};
        TblB.SetWidths(Awidthss);

PdfPCell B1 = new PdfPCell(new Phrase(10, " ", f3));
        B1.BackgroundColor = new BaseColor(ColorTranslator.FromHtml("#e9e9e9"));
        TblB.AddCell(B1);
        TblB.AddCell(new PdfPCell(new Phrase(50, txtComments.Text, f3)));

 Document pdfDoc = new Document(PageSize.A4, 10f, 10f, 10f, 0f);
            PdfWriter.GetInstance(pdfDoc, Page.Response.OutputStream);
            pdfDoc.Open();

And here is my Textbox:

<asp:TextBox
        ID="txtComments"
        TextMode="MultiLine"
        Columns="50"
        Rows="20"
        Runat="server"  Width="855px" />