using iTextSharp.text.pdf;

/* Code Snippet */

using (var dia = new SaveFileDialog())

{

    dia.Filter = @"PDF files|*.pdf";

    dia.FileName = string.Format("PDF_{0}", DateTime.Today.ToString("yyyy-MM-dd"));

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

    {

        using (FileStream fsWrite = new FileStream(dia.FileName, FileMode.OpenOrCreate, FileAccess.Write))

        {

            using (var reader = new PdfReader(@"\Templates\PDFTemplate\Template01.pdf"))

            {

                using (var stamper = new PdfStamper(reader, fsWrite))

                {

                    stamper.Writer.CloseStream = false;

                    // 保留表单域，允许继续编辑

                    stamper.FormFlattening = false;

                    // 更新表单域字段

                    var form = stamper.AcroFields;

                    form.SetField("form1[0].#subform[0].flt_txtUserName[0]", "username");

                    stamper.Close();

                }

            }

        }

        MessageBox.Show("Report has been exported", Resources.Common_Successed, MessageBoxButtons.OK, MessageBoxIcon.Information);

    }

}