private void button1_Click(object sender, EventArgs e)
        {
            //Document:（文档）生成pdf必备的一个对象,生成一个Document示例
            Document document = new Document(PageSize.A4, 30, 30, 5, 5);
            //为该Document创建一个Writer实例： 
            PdfWriter.GetInstance(document, new FileStream("Chap0101.pdf", FileMode.Create)); 
            //打开当前Document
            document.Open();

            //为当前Document添加内容：
             document.Add(new Paragraph("Hello World"));           
            //另起一行。有几种办法建立一个段落，如： 
            Paragraph p1 = new Paragraph(new Chunk("This is my first paragraph.\n", FontFactory.GetFont(FontFactory.HELVETICA, 12))); 
            Paragraph p2 = new Paragraph(new Phrase("This is my second paragraph.", FontFactory.GetFont(FontFactory.HELVETICA, 12))); 
            Paragraph p3 = new Paragraph("This is my third paragraph.", FontFactory.GetFont(FontFactory.HELVETICA, 12)); 
            //所有有些对象将被添加到段落中：
            p1.Add("you can add string here\n\t"); 
            p1.Add(new Chunk("you can add chunks \n")); p1.Add(new Phrase("or you can add phrases.\n"));
            document.Add(p1); document.Add(p2); document.Add(p3);

            //创建了一个内容为“hello World”、红色、斜体、COURIER字体、尺寸20的一个块： 
            Chunk chunk = new Chunk("Hello world", FontFactory.GetFont(FontFactory.COURIER, 20, iTextSharp.text.Font.COURIER, new iTextSharp.text.Color(255, 0, 0)));
            document.Add(chunk);
            //如果你希望一些块有下划线或删除线，你可以通过改变字体风格简单做到： 
            Chunk chunk1 = new Chunk("This text is underlined", FontFactory.GetFont(FontFactory.HELVETICA, 12, iTextSharp.text.Font.UNDEFINED));
            Chunk chunk2 = new Chunk("This font is of type ITALIC | STRIKETHRU", FontFactory.GetFont(FontFactory.HELVETICA, 12, iTextSharp.text.Font.ITALIC | iTextSharp.text.Font.STRIKETHRU));
            //改变块的背景
            chunk2.SetBackground(new iTextSharp.text.Color(0xFF, 0xFF, 0x00));
            //上标/下标
            chunk1.SetTextRise(5);
            document.Add(chunk1);
            document.Add(chunk2);

            //外部链接示例： 
            Anchor anchor = new Anchor("website", FontFactory.GetFont(FontFactory.HELVETICA, 12, iTextSharp.text.Font.UNDEFINED, new iTextSharp.text.Color(0, 0, 255))); 
            anchor.Reference = "http://itextsharp.sourceforge.net/";
            anchor.Name = "website"; 
            //内部链接示例： 
            Anchor anchor1 = new Anchor("This is an internal link\n\n"); 
            anchor1.Name = "link1"; 
            Anchor anchor2 = new Anchor("Click here to jump to the internal link\n\f"); 
            anchor2.Reference = "#link1";
            document.Add(anchor);document.Add(anchor1);document.Add(anchor2);

            //排序列表示例： 
            List list = new List(true, 20); 
            list.Add(new ListItem("First line")); 
            list.Add(new ListItem("The second line is longer to see what happens once the end of the line is reached. Will it start on a new line?")); 
            list.Add(new ListItem("Third line"));
            document.Add(list);

            //文本注释： 
            Annotation a = new Annotation("authors","Maybe its because I wanted to be an author myself that I wrote iText.");
            document.Add(a);

            //包含页码没有任何边框的页脚。 
            HeaderFooter footer = new HeaderFooter(new Phrase("This is page: "), true); 
            footer.Border = iTextSharp.text.Rectangle.NO_BORDER;
            document.Footer = footer;

            //Chapter对象和Section对象自动构建一个树：
            iTextSharp.text.Font f1 = new iTextSharp.text.Font();
            f1.SetStyle(iTextSharp.text.Font.BOLD);
            Paragraph cTitle = new Paragraph("This is chapter 1", f1);
            Chapter chapter = new Chapter(cTitle, 1);
            Paragraph sTitle = new Paragraph("This is section 1 in chapter 1", f1); 
            Section section = chapter.AddSection(sTitle, 1); 
            document.Add(chapter);
             
            //构建了一个简单的表： 
            Table aTable = new Table(4, 4);
            aTable.AutoFillEmptyCells = true;
            aTable.AddCell("2.2", new Point(2, 2));
            aTable.AddCell("3.3", new Point(3, 3));
            aTable.AddCell("2.1", new Point(2, 1));
            aTable.AddCell("1.3", new Point(1, 3));
            document.Add(aTable);
            //构建了一个不简单的表：
            Table table = new Table(3);
            table.BorderWidth = 1;
            table.BorderColor = new iTextSharp.text.Color(0, 0, 255);
            table.Cellpadding = 5;
            table.Cellspacing = 5;
            Cell cell = new Cell("header");
            cell.Header = true;
            cell.Colspan = 3;
            table.AddCell(cell);
            cell = new Cell("example cell with colspan 1 and rowspan 2");
            cell.Rowspan = 2;
            cell.BorderColor = new iTextSharp.text.Color(255, 0, 0);
            table.AddCell(cell);
            table.AddCell("1.1");
            table.AddCell("2.1");
            table.AddCell("1.2");
            table.AddCell("2.2");
            table.AddCell("cell test1");
            cell = new Cell("big cell");
            cell.Rowspan = 2;
            cell.Colspan = 2;
            cell.BackgroundColor = new iTextSharp.text.Color(0xC0, 0xC0, 0xC0);
            table.AddCell(cell);
            table.AddCell("cell test2");
            // 改变了单元格“big cell”的对齐方式： 
            cell.HorizontalAlignment = Element.ALIGN_CENTER; 
            cell.VerticalAlignment = Element.ALIGN_MIDDLE;
            document.Add(table);

            //关闭Document
            document.Close();
            
        }