实现一个PDF文件下载功能，涉及到页眉页脚，段落，图片的生成。itextsharp功能强大，类库繁多。
先来看下最后实现的效果：
下面来看代码
添加引用：itextsharp.dll
帮助类的代码，这个类可以直接使用，如果你需要增加或者完善某功能，可以对其进行修改。
此类使用方法下面做介绍：
public class HeaderAndFooterEvent : PdfPageEventHelper, IPdfPageEvent
{
#region 静态字段
public static PdfTemplate tpl = null;
public static bool PAGE_NUMBER = false;//为True时就生成 页眉和页脚
public static iTextSharp.text.Rectangle rect = PageSize.A4; //文档大小
/// <summary>
/// 正文字体
/// </summary>
private static Font font;
/// <summary>
/// 页眉页脚字体
/// </summary>
public static string HeaderFooterFontName = "黑体";
/// <summary>
/// 页头页脚字号
/// </summary>
public static int HeaderFooterFontSize = 10;
/// <summary>
/// 页头页尾字体颜色
/// </summary>
public static BaseColor HeaderFooterFontColor = BaseColor.BLACK;
/// <summary>
/// 左边页眉
/// </summary>
public static string HeaderLeft { get; set; }
/// <summary>
/// 右边页眉
/// </summary>
public static string HeaderRight { get; set; }
/// <summary>
/// 左边页脚
/// </summary>
public static string FooterLeft { get; set; }
/// <summary>
/// 右边页脚
/// </summary>
public static string FooterRight { get; set; }
#endregion
#region 设置页面大小
/// <summary>
/// 设置页面大小
/// </summary>
/// <param name="type">页面大小(如"A4")</param>
public static void SetPageSize(string type)
{
switch (type.Trim())
{
case "A4":
rect = PageSize.A4;
break;
case "A8":
rect = PageSize.A8;
break;
}
}
#endregion
#region 设置字体
/// <summary>
/// 设置字体
/// </summary>
/// <param name="size">字体大小</param>
public static void SetFont(BaseColor color, string fontName = "华文中宋", float size = 12, int style = Font.NORMAL)
{
font = new Font(BaseFontAndSize(fontName), size, style, color);
}
#endregion
#region 生成页眉页脚
/// <summary>
/// 关闭一个页面时发生
/// </summary>
public override void OnEndPage(PdfWriter writer, Document document)
{
if (PAGE_NUMBER)
{
Font HeaderFooterFont = FontAndSize(HeaderFooterFontName, HeaderFooterFontSize, Font.NORMAL, HeaderFooterFontColor);
Phrase header_left = new Phrase(HeaderLeft, HeaderFooterFont);
Phrase header_right = new Phrase(HeaderRight, HeaderFooterFont);
Phrase footer_left = new Phrase(FooterLeft, HeaderFooterFont);
Phrase footer_center = new Phrase("第" + (writer.PageNumber) + "页/共 页", HeaderFooterFont);
Phrase footer_right = new Phrase(FooterRight, HeaderFooterFont);
PdfContentByte cb = writer.DirectContent;
//模版 显示总共页数
cb.AddTemplate(tpl, document.Right - 290 + document.LeftMargin, document.Bottom - 15);//调节模版显示的位置
//页眉显示的位置
ColumnText.ShowTextAligned(cb, Element.ALIGN_CENTER, header_right,
document.Right - 50 + document.LeftMargin, document.Top + 15, 0);
ColumnText.ShowTextAligned(cb, Element.ALIGN_CENTER, header_left,
document.Right - 500 + document.LeftMargin, document.Top + 15, 0);
//页脚显示的位置
ColumnText.ShowTextAligned(cb, Element.ALIGN_CENTER, footer_left,
document.Right - 535 + document.LeftMargin, document.Bottom - 15, 0);
ColumnText.ShowTextAligned(cb, Element.ALIGN_CENTER, footer_center,
document.Right - 300 + document.LeftMargin, document.Bottom - 15, 0);
ColumnText.ShowTextAligned(cb, Element.ALIGN_CENTER, footer_right,
document.Right - 80 + document.LeftMargin, document.Bottom - 15, 0);
}
}
/// <summary>
/// 打开一个新页面时发生
/// </summary>
public override void OnStartPage(PdfWriter writer, Document document)
{
if (PAGE_NUMBER)
{
writer.PageCount = writer.PageNumber - 1;
}
}
/// <summary>
/// 关闭PDF文档时发生该事件
/// </summary>
public override void OnCloseDocument(PdfWriter writer, Document document)
{
BaseFont bf = BaseFontAndSize(HeaderFooterFontName);
tpl.BeginText();
tpl.SetFontAndSize(bf, HeaderFooterFontSize);
tpl.ShowText((writer.PageNumber - 1).ToString());//总页数
tpl.EndText();
tpl.ClosePath();
}
#endregion
#region 私有方法
private static Font FontAndSize(string font_name, int size, int style, BaseColor baseColor)
{
BaseFont baseFont;
BaseFont.AddToResourceSearch("iTextAsian.dll");
BaseFont.AddToResourceSearch("iTextAsianCmaps.dll");
Font font = null;
string file_name = "";
int fontStyle;
switch (font_name)
{
case "黑体":
file_name = "SIMHEI.TTF";
break;
case "华文中宋":
file_name = "STZHONGS.TTF";
break;
case "宋体":
file_name = "SIMYOU.TTF";
break;
default:
file_name = "SIMYOU.TTF";
break;
}
baseFont = BaseFont.CreateFont(@"c:/windows/fonts/" + file_name, BaseFont.IDENTITY_H, BaseFont.NOT_EMBEDDED);
if (style < -1)
{
fontStyle = Font.NORMAL;
}
else
{
fontStyle = style;
}
font = new Font(baseFont, size, fontStyle, baseColor);
return font;
}
private static BaseFont BaseFontAndSize(string font_name)
{
BaseFont baseFont;
BaseFont.AddToResourceSearch("iTextAsian.dll");
BaseFont.AddToResourceSearch("iTextAsianCmaps.dll");
string file_name = "";
switch (font_name)
{
case "黑体":
file_name = "SIMHEI.TTF";
break;
case "华文中宋":
file_name = "STZHONGS.TTF";
break;
case "宋体":
file_name = "SIMYOU.TTF";
break;
default:
file_name = "SIMYOU.TTF";
break;
}
baseFont = BaseFont.CreateFont(@"c:/windows/fonts/" + file_name, BaseFont.IDENTITY_H, BaseFont.NOT_EMBEDDED);
return baseFont;
}
#endregion
#region 添加段落
/// <summary>
/// 添加段落
/// </summary>
/// <param name="content">内容</param>
/// <param name="Alignment">对齐方式（1为居中，0为居左，2为居右）</param>
/// <param name="SpacingAfter">段后空行数（0为默认值）</param>
/// <param name="SpacingBefore">段前空行数（0为默认值）</param>
/// <param name="MultipliedLeading">行间距（0为默认值）</param>
public static Paragraph AddParagraph(string content, int Alignment, float SpacingAfter, float SpacingBefore, float MultipliedLeading)
{
Paragraph pra = new Paragraph(content, font);
pra.Alignment = Alignment;
pra.SpacingAfter = SpacingAfter;
pra.SpacingBefore = SpacingBefore;
pra.MultipliedLeading = MultipliedLeading;
return pra;
}
public static Paragraph AddParagraph(string content, int Alignment, float MultipliedLeading)
{
Paragraph pra = new Paragraph(content, font);
pra.Alignment = Alignment;
pra.MultipliedLeading = MultipliedLeading;
return pra;
}
public static void AddPhrase(PdfWriter writer, Document document, string content, float marginLift, float marginBottom)
{
Phrase phrase = new Phrase(content, font);
PdfContentByte cb = writer.DirectContent;
ColumnText.ShowTextAligned(cb, Element.ALIGN_CENTER, phrase,
marginLift + document.LeftMargin, marginBottom, 0);
}
#endregion
#region 添加图片
/// <summary>
/// 添加图片
/// <param name="Alignment">对齐方式 (0/1/2)</param>
/// <param name="marginRight">页边距</param>
/// <param name="marginBottom">页边距</param>
/// </summary>
public static iTextSharp.text.Image AddImage(string path, int Alignment, float marginRight, float marginBottom)
{
Image img = Image.GetInstance(new Uri(path));
img.Alignment = Alignment;
//等比缩放，宽与高的缩放系数哪个大就取哪一个（比如高的系数是0.8，宽的是0.7，则取0.7。这样图片就不会超出页面范围）
if (img.Width > img.Height)
{
//这里计算图片的缩放系数，因为图片width>height,所以将图片旋转90度以适应页面，计算缩放系数的时候宽与高对调
float PageHeight = PageSize.A4.Height - marginBottom * 3;
double percentHeight = Math.Round((PageHeight / img.Width), 2);
float PageWidth = PageSize.A4.Width - marginRight * 2;
double percentWidth = Math.Round((PageWidth / img.Height), 2);
double percent = percentHeight > percentWidth ? percentWidth : percentHeight;
img.ScalePercent((float)percent * 100);
img.RotationDegrees = 90f;
}
else
{
float PageHeight = PageSize.A4.Height - marginBottom * 3;
double percentHeight = Math.Round((PageHeight / img.Height), 2);
float PageWidth = PageSize.A4.Width - marginRight * 2;
double percentWidth = Math.Round((PageWidth / img.Width), 2);
double percent = percentHeight > percentWidth ? percentWidth : percentHeight;
img.ScalePercent((float)percent * 100);
}
return img;
}
#endregion
}
下面是使用方法：
在你需要生成文件的地方实例化Document和PdfWriter 对象：
Document document = new Document(HeaderAndFooterEvent.rect);
//此处使用的是http请求的流，你也可以使用文件流Stream
PdfWriter writer = PdfWriter.GetInstance(document, HttpContext.Current.Response.OutputStream);
document.Open();
writer.PageEvent = new HeaderAndFooterEvent();
实现页眉和页脚：
HeaderAndFooterEvent.PAGE_NUMBER = true;//实现页眉跟页脚
HeaderAndFooterEvent.tpl = writer.DirectContent.CreateTemplate(500, 500); //定义模板
HeaderAndFooterEvent.HeaderLeft = "Aviation Meteorological Center";
HeaderAndFooterEvent.HeaderRight = "民航气象中心";
HeaderAndFooterEvent.FooterLeft = "TEL:010-87922095";
HeaderAndFooterEvent.FooterRight = _dtm.ToString("yyyy-MM-dd HH:mm:ss") + "(UTC)";
首页
//每次在添加文本内容之前可以先设置字体，有效期持续到重新设置之前
HeaderAndFooterEvent.SetFont(BaseColor.BLACK, "宋体", 25, Font.BOLD);
//添加一个空段落来占位，五个参数分别为：内容，对齐方式（1为居中，0为居左，2为居右），段后空行数，段前空行数，行间距
document.Add(HeaderAndFooterEvent.AddParagraph(" ", 1, 200, 0, 1.5f));
//这个方法为上一个方法的重载，三个参数分别为：内容，对齐方式，行间距
document.Add(HeaderAndFooterEvent.AddParagraph("飞行气象文件", 1, 1.5f));
HeaderAndFooterEvent.SetFont(BaseColor.BLACK, "宋体", 18, Font.BOLD);
document.Add(HeaderAndFooterEvent.AddParagraph("Meteorological Aviation Report", 1, 1.5f));
然后就是新建页了，每需要一页的时候就 document.NewPage(); 就可以了，当然，如果你在其中一页添加的内容超过了此页的篇幅，则会自动追加一页。下面演示怎么新建一页并添加内容：
document.NewPage();
HeaderAndFooterEvent.SetFont(BaseColor.DARK_GRAY, "宋体", 15, Font.BOLD);
document.Add(HeaderAndFooterEvent.AddParagraph("飞行气象文件", 1, 1.5f));
HeaderAndFooterEvent.SetFont(BaseColor.DARK_GRAY, "宋体", 12);
document.Add(HeaderAndFooterEvent.AddParagraph("航班号： " ));
下面演示添加图片：
添加图片比较简单，当图片的宽度超过高度时，会进行旋转并按照比例缩放，从而尽量铺满整个页面。如果你不需要旋转，可以对帮助类进行修改。
document.NewPage();
//四个参数分别为：图片路径，对齐方式，文档的右边距，下边距；边距这两个参数用于计算图片的缩放尺寸。
document.Add("图片路径", 0, document.RightMargin, document.Bottom));
到现在，大功告成
只需要关闭文档和流就行了。
writer.Flush();
writer.CloseStream = true;
document.Close();
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原文链接：https://blog.csdn.net/c79651760/article/details/56480109