[C#]使用iText7.pdfHtml，以HTML为模板，转换成PDF打印

2021-07-07 05:40:06

使用iText7的pdfHtml库，将html转成pdf，官方：https://itextpdf.com/en/demos/convert-html-css-to-pdf-free-online；

官方示例：

using System.IO;
using iText.Html2pdf;

namespace WebsiteDemoPdfHtml
{
    class Program
    {
        private static string ORIG = "/uploads/input.html";
        private static string OUTPUT_FOLDER = "/myfiles/";

        static void Main(string[] args)
        {
            string pdfDest = OUTPUT_FOLDER + "output.pdf";
            HtmlConverter.ConvertToPdf(new FileStream(ORIG, FileMode.Open), new FileStream(pdfDest, FileMode.Create));
        }
    }
}

官方可以下载到详细的使用文档；支持CSS3；支持css @page规则控制打印设置选项；

以html作为打印模板，往往需要打印多项数据，我的实现是这样的（与官方模板不同）：使用双大括号{{field}}作为书签，使用正则替换插入数据；如果有列表数据，则以注释作为子模板开始，以作为子模版结束；

hello.html文件：

<!DOCTYPE html>

<html lang="zh-cn" xmlns="http://www.w3.org/1999/xhtml">
<head>
    <meta charset="utf-8" />
    <title>Colossal</title>
    <meta name="description" content="Gloria is an out-of-work party girl ..." />
    <style>
        @page {
            @bottom-right {
                content: "Page "counter(page)" of "counter(pages);
            }
        }

        .poster {
            width: 120px;
            float: right;
        }

        .director {
            font-style: italic;
        }

        body {
            font-family: serif;
        }

        .imdb {
            font-size: 0.8em;
        }

        a {
            color: red;
        }
    </style>
</head>
<body>
    <img src="{{ImageUrl}}" class="poster" />
    <h1>{{Title}}</h1>
    <div class="director">{{Director}}</div>
    <div class="description">{{Description}}</div>
    <div class="imdb">{{Imdb}}<a href="{{Href}}">{{HrefContent}}</a></div>
    <ul>
        <!--names-start-->
        <li>{{Name}}</li>
        <!--names-end-->
    </ul>
</body>
</html>

View Code

示例代码：

var pdfDest = "myfiles/" + "hello.pdf";

var pdfWriter = new PdfWriter (pdfDest);
var pdf = new PdfDocument (pdfWriter);

var pageSize = PageSize.A4; // 设置默认页面大小，css @page规则可覆盖这个
pdf.SetDefaultPageSize (pageSize);

var mediaDeviceDescription = new MediaDeviceDescription (MediaType.PRINT); // 指当前设备类型，如果是预览使用SCREEN
mediaDeviceDescription.SetWidth (pageSize.GetWidth ());

var properties = new ConverterProperties ();
properties.SetBaseUri ("htmls"); // 设置根目录
properties.SetCharset ("utf-8");

var provider = new DefaultFontProvider (true, true, true); // 第三个参数为True，以支持系统字体，否则不支持中文
properties.SetFontProvider (provider);

properties.SetMediaDeviceDescription (mediaDeviceDescription);

var dic = new Dictionary<String, String> {
        ["{{ImageUrl}}"] = "./test_files/5687441010153797724.jpg",
        ["{{Title}}"] = "Colossal (2016) 中文字体",
        ["{{Director}}"] = "Directed by Nacho Vigalondo",
        ["{{Description}}"] = "Gloria is an out-of-work party girl forced to leave her life in New York City,and move  back home. When reports surface that a giant creature isdestroying Seoul, she gradually comes to the realization that she issomehow connected to this phenomenon.",
        ["{{Imdb}}"] = "Read more about this movie on",
        ["{{Href}}"] = "www.imdb.com/title/tt4680182",
        ["{{HrefContent}}"] = "IMDB"
    };

var htmlTemplate = File.ReadAllText ("htmls/hello.html");

var match = Regex.Match (htmlTemplate, @"<!--names-start-->(.|\s)+?<!--names-end-->"); // 匹配子模版

if (match == null)
    return;

var template = match.Value.Substring ("<!--names-start-->".Length, match.Value.Length - "<!--names-start--><!--names-end-->".Length);
var names = new List<String> { "张三", "李四", "王五" };

var sb = new StringBuilder ("<!--names-start-->");

foreach (var name in names) {
    sb.Append (template.Replace ("{{Name}}", name)); // 子模版赋值
}

sb.Append ("<!--names-end-->");

htmlTemplate = htmlTemplate.Replace (match.Value, sb.ToString ()); // 完成子模版部分

var regex = new Regex (String.Join ("|", dic.Keys));
var html = regex.Replace (htmlTemplate, m => dic[m.Value]); // 模板字段赋值

HtmlConverter.ConvertToPdf (html, pdf, properties);

View Code

实现效果：

[C#]使用iText7.pdfHtml，以HTML为模板，转换成PDF打印

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