Export To PDF ,The filtered rows of DATA GRID VIEW

I have a datagrid view,now my intention is to make it to PDF export for the filtered column

My code is below:

BaseFont bf = BaseFont.CreateFont(BaseFont.TIMES_ROMAN,BaseFont.CP1250,BaseFont.EMBEDDED);

PdfPTable table = new PdfPTable(dgv.Columns.Count);

table.DefaultCell.Padding = 3;

table.WidthPercentage = 100;

table.HorizontalAlignment = Element.ALIGN_LEFT;

table.DefaultCell.BorderWidth = 1;

iTextSharp.text.Font txt=new iTextSharp.text.Font(bf,10f, iTextSharp.text.Font.NORMAL);

//ADD HEADER

foreach (DataGridViewColumn colmn in dgv.Columns)

{

PdfPCell cell = new PdfPCell(new Phrase(colmn.HeaderText,txt));

cell.BackgroundColor = new iTextSharp.text.BaseColor(245, 245, 220);

table.AddCell(cell);

}

//ADD DATAGRID

foreach (DataGridViewRow row in dgv.Rows)

{

foreach (DataGridViewCell dcell in row.Cells)

{

table.AddCell(new Phrase(dcell.Value.ToString(), txt));

}

var SaveFileDialog = new SaveFileDialog();

SaveFileDialog.FileName = filename;

SaveFileDialog.DefaultExt = ".pdf ";

if (SaveFileDialog.ShowDialog() == DialogResult.OK)

{

using (FileStream stream = new FileStream(SaveFileDialog.FileName, FileMode.Create))

{

Document doc = new Document(PageSize.A4, 10f, 10f, 42f, 35f);

PdfWriter wri = PdfWriter.GetInstance(doc, stream);

doc.Open();

doc.Add(table);

doc.Close();

stream.Close();

}