c#

OpenFileDialog dlg = new OpenFileDialog();
            dlg.Filter = "PDF Files(.PDF) |* .PDF|All Files(.)|*.*";
            dlg.RestoreDirectory = true;

            if (dlg.ShowDialog() == DialogResult.OK)
            {
                string strText = string.Empty;
                PdfReader reader = new PdfReader(dlg.FileName);

                for (int page = 1; page < reader.NumberOfPages; page++)
                {
                    ITextExtractionStrategy its = new LocationTextExtractionStrategy();
                    String s = PdfTextExtractor.GetTextFromPage(reader, page, its);
                    strText += s;
                }

                richTextBox1.Text = strText;

                reader.Close();
            }