C#怎么将 HTML转换为图片或 PDF？
16lz
2021-01-22
首先是把 HTML 转换为图片。
public partial class Form1 : Form {public Form1() { InitializeComponent(); } WebBrowser webBrowser = null;public void ConvertToImg() { webBrowser = new WebBrowser();//是否显式滚动条webBrowser.ScrollBarsEnabled = false;//加载HTML页面的地址webBrowser.Navigate(""); //页面加载完成执行事件webBrowser.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(webBrowser_DocumentCompleted); }private void webBrowser_DocumentCompleted(object sender, EventArgs e)//这个就是当网页载入完毕后要进行的操作 {//获取解析后HTML的大小System.Drawing.Rectangle rectangle = webBrowser.Document.Body.ScrollRectangle;int width = rectangle.Width;int height = rectangle.Height;//设置解析后HTML的可视区域webBrowser.Width = width; webBrowser.Height = height; Bitmap bitmap = new System.Drawing.Bitmap(width, height); webBrowser.DrawToBitmap(bitmap, new System.Drawing.Rectangle(0, 0, width, height));//设置图片文件保存路径和图片格式，格式可以自定义string filePath = AppDomain.CurrentDomain.BaseDirectory + "../../SaveFIle/" + DateTime.Now.ToString("yyyyMMddHHmmssfff") + ".png"; bitmap.Save(filePath, System.Drawing.Imaging.ImageFormat.Png); }private void button1_Click(object sender, EventArgs e) { ConvertToImg(); } }View Code上面这种方法是解析指定URL地址的HTML，然后转换为图片。当然，也可以直接写一些HTML标签。如下：
public partial class Form1 : Form {public Form1() { InitializeComponent(); } WebBrowser webBrowser = null;public void ConvertToImg() {string html = "<div><table border = \"1\" cellspacing = \"0\" cellpadding = \"3\" style = \"text-align:center;\"><tr><th style = \"width:60px;\">字段1</th><th style = \"width:60px;\">字段2</th><th style = \"width:60px;\">字段3</th></tr><tr style = \"color:green;\"><td>小明</td><td>22</td><td>185</td></tr><tr style = \"color:red;\"><td>小青</td><td>21</td><td>170</td></tr></table></div>"; webBrowser = new WebBrowser();//是否显式滚动条webBrowser.ScrollBarsEnabled = false;//加载 htmlwebBrowser.DocumentText = html; //页面加载完成执行事件webBrowser.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(webBrowser_DocumentCompleted); }private void webBrowser_DocumentCompleted(object sender, EventArgs e)//这个就是当网页载入完毕后要进行的操作 {//获取解析后HTML的大小System.Drawing.Rectangle rectangle = webBrowser.Document.Body.ScrollRectangle;int width = rectangle.Width;int height = rectangle.Height;//设置解析后HTML的可视区域webBrowser.Width = width; webBrowser.Height = height; Bitmap bitmap = new System.Drawing.Bitmap(width, height); webBrowser.DrawToBitmap(bitmap, new System.Drawing.Rectangle(0, 0, width, height));//设置图片文件保存路径和图片格式，格式可以自定义string filePath = AppDomain.CurrentDomain.BaseDirectory + "../../SaveFIle/" + DateTime.Now.ToString("yyyyMMddHHmmssfff") + ".png"; bitmap.Save(filePath, System.Drawing.Imaging.ImageFormat.Png); }private void button1_Click(object sender, EventArgs e) { ConvertToImg(); } }View Code
然后把图片转换为PDF，这里需要用到 iTextSharp.dll 这个组件。
public partial class Form1 : Form {public Form1() { InitializeComponent(); } WebBrowser webBrowser = null;public void ConvertToImg() {string html = "<div><table border = \"1\" cellspacing = \"0\" cellpadding = \"3\" style = \"text-align:center;\"><tr><th style = \"width:60px;\">字段1</th><th style = \"width:60px;\">字段2</th><th style = \"width:60px;\">字段3</th></tr><tr style = \"color:green;\"><td>小明</td><td>22</td><td>185</td></tr><tr style = \"color:red;\"><td>小青</td><td>21</td><td>170</td></tr></table></div>"; webBrowser = new WebBrowser();//是否显式滚动条webBrowser.ScrollBarsEnabled = false;//加载 htmlwebBrowser.DocumentText = html; //页面加载完成执行事件webBrowser.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(webBrowser_DocumentCompleted); }private void webBrowser_DocumentCompleted(object sender, EventArgs e)//这个就是当网页载入完毕后要进行的操作 {//获取解析后HTML的大小System.Drawing.Rectangle rectangle = webBrowser.Document.Body.ScrollRectangle;int width = rectangle.Width;int height = rectangle.Height;//设置解析后HTML的可视区域webBrowser.Width = width; webBrowser.Height = height; Bitmap bitmap = new System.Drawing.Bitmap(width, height); webBrowser.DrawToBitmap(bitmap, new System.Drawing.Rectangle(0, 0, width, height));//设置图片文件保存路径和图片格式，格式可以自定义string filePath = AppDomain.CurrentDomain.BaseDirectory + "../../SaveFIle/" + DateTime.Now.ToString("yyyyMMddHHmmssfff") + ".png"; bitmap.Save(filePath, System.Drawing.Imaging.ImageFormat.Png);//创建PDFFileStream fileStream = new FileStream(AppDomain.CurrentDomain.BaseDirectory + "../../SaveFIle/" + DateTime.Now.ToString("yyyyMMddHHmmssfff") + ".pdf", FileMode.Create);byte[] result = CreatePDF(bitmap, width, height); fileStream.Write(result, 0, result.Length); fileStream.Close(); fileStream.Dispose(); }private void button1_Click(object sender, EventArgs e) { ConvertToImg(); }public byte[] CreatePDF(Bitmap bitmap, int width, int height) {using (MemoryStream ms = new MemoryStream()) { Document doc = new Document(new iTextSharp.text.Rectangle(0, 0, width, height), 3, 3, 3, 3); // 左右上下PdfWriter writer = PdfWriter.GetInstance(doc, ms); writer.CloseStream = false; doc.Open(); iTextSharp.text.Image img = iTextSharp.text.Image.GetInstance(bitmap, System.Drawing.Imaging.ImageFormat.Png); img.ScalePercent(100); // 放缩比例doc.Add(img); // 添加图片对像 doc.Close();return ms.ToArray(); } } }View Code不过这种生成图片之后再转成PDF，会造成像素的丢失，所以看起来要比图片模糊一点。
还有一种办法就是直接生成PDF，这里需要安装 ABCpdf。不过，这个是收费的。。。
public partial class Form1 : Form {public Form1() { InitializeComponent(); }public void ConvertToPDF() {string html = "<div><table border = \"1\" cellspacing = \"0\" cellpadding = \"3\" style = \"text-align:center;\"><tr><th style = \"width:60px;\">字段1</th><th style = \"width:60px;\">字段2</th><th style = \"width:60px;\">字段3</th></tr><tr style = \"color:green;\"><td>小明</td><td>22</td><td>185</td></tr><tr style = \"color:red;\"><td>小青</td><td>21</td><td>170</td></tr></table></div>";//创建一个Doc对象Doc doc = new Doc();//Rect默认是文档整个页面大小,这里的Inset表示将Rect左右留出15的空白,上下留出20的空白doc.Rect.Inset(15, 20);//直接设置htmlint docID = doc.AddHtml(html);//设置URL//int docID = doc.AddImageUrl("");//设置字体doc.AddFont("Arial");while (true) {//判断是否还有内容if (!doc.Chainable(docID)) {break; }//如果还有内容就添加一页doc.Page = doc.AddPage();//根据ID添加内容并返回页面上该内容对应的新IDdocID = doc.AddImageToChain(docID); }string filePath = AppDomain.CurrentDomain.BaseDirectory + "../../SaveFIle/" + DateTime.Now.ToString("yyyyMMddHHmmssfff") + ".pdf"; doc.Save(filePath); doc.Clear(); doc.Dispose(); }private void button1_Click(object sender, EventArgs e) { ConvertToPDF(); } }View Code
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