在ASP.NET Web表单中使用C＃将Web表单内容转换为PDF

Question

我在for循环中调用ExportToPDF2方法来生成pdf文档。

问题是Respons.End()之后循环停止。

如何解决此问题，有没有比使用此技术更好的方法？

private int ExportToPDF2()
{
    using (StringWriter sw = new StringWriter())
    {
        using (HtmlTextWriter hw = new HtmlTextWriter(sw))
        {
            Page.RenderControl(hw);
            StringReader sr = new StringReader(sw.ToString());
            Document pdfDoc = new Document(PageSize.A4, 10f, 10f, 10f, 0f);
            PdfWriter writer = PdfWriter.GetInstance(pdfDoc, Response.OutputStream);
            pdfDoc.Open();
            XMLWorkerHelper.GetInstance().ParseXHtml(writer, pdfDoc, sr);
            pdfDoc.Close();
            Response.ContentType = "application/pdf";
            Response.AddHeader("content-disposition", "attachment;filename=GridViewExport.pdf");
            Response.Cache.SetCacheability(HttpCacheability.NoCache);
            Response.Write(pdfDoc);
            Response.End();
        }                
    }
    return 0;
}

Answer 1

让我奇怪的是，您多次保存同一页面（ Page.RenderControl(hw); ）的输出！

无论如何，不​​可能从服务器发送多个outputStream，您可以尝试

Response.Write(somefile);
Response.End();
textBox1.Text = "1111"; // it wont work because you can't have multiple outputstream

最好的解决方法是制作一个zip文件，然后执行Response.Write(zipFile)

但是，如果仍然坚持将它们分开（多次下载）更好，则可以通过以下方法首先将每个文件保存在服务器上：

using (HtmlTextWriter hw = new HtmlTextWriter(sw))
{
  Page.RenderControl(hw);
  StringReader sr = new StringReader(sw.ToString());
  Document pdfDoc = new Document(PageSize.A4, 10f, 10f, 10f, 0f);
  PdfWriter.GetInstance(pdfDoc, new FileStream(Server.MapPath("~") + pdfName + ".pdf");
} 

然后使用此技巧https://stackoverflow.com/a/30682695/336511支持多个下载。 请注意，这将适用于现代浏览器。

var links = [
  'https://s3.amazonaws.com/Minecraft.Download/launcher/Minecraft.exe',
  'https://s3.amazonaws.com/Minecraft.Download/launcher/Minecraft.dmg',
  'https://s3.amazonaws.com/Minecraft.Download/launcher/Minecraft.jar'
];

function downloadAll(urls) {
  var link = document.createElement('a');

  link.setAttribute('download', null);
  link.style.display = 'none';

  document.body.appendChild(link);

  for (var i = 0; i < urls.length; i++) {
    link.setAttribute('href', urls[i]);
    link.click();
  }

  document.body.removeChild(link);
}
<button onclick="downloadAll(window.links)">Test me!</button>