protected void pdfButton_Click(object sender, EventArgs e)
{
PDFManager aPdfManager = new PDFManager();
Document pdfDocument = new Document(PageSize.A4, 50f, 50f, 50f, 50f);
PdfWriter.GetInstance(pdfDocument, Response.OutputStream);
pdfDocument.Open();
pdfDocument.Add(aPdfManager.GetUnpaidBillReportPdfParagraph(fromDateTextBox.Text, toDateTextBox.Text, unpaidBillReportGridView, totalTextBox.Text));
pdfDocument.Close();
fromDateTextBox.Text = string.Empty;
toDateTextBox.Text = string.Empty;
unpaidBillReportGridView.DataSource = null;
unpaidBillReportGridView.DataBind();
totalTextBox.Text = String.Empty;
Response.ContentType = "application/pdf";
Response.AppendHeader("content-disposition", "attachment;filename=UnpaidBillReport.pdf");
Response.Write(pdfDocument);
Response.Flush();
Response.End();
}