如何解决在 ASP.net core 3.1 Razor Pages 中打印 PDF
为了学习 ASP.net 核心，我使用 ASP.NET 核心 3.1 创建了一个简单的 CRUD 应用程序。我想将我的详细信息页面打印为发票。我环顾四周，似乎在完整的 .Net Framework 中打印 PDF 更可用。
谁能指出我正确的方向？我遇到过像 SelectPDF、WKHTMLTOPDF、PDFSharp 这样的免费库，但坦率地说，这些样本是 pre-asp.net 核心，不能安静地将它与 asp.net 核心 Razor Pages 集成。实际上，如果我没记错的话，上面提到的一些库与 Razor Pages Core 不兼容。
解决方法
免责声明：我为 SelectPdf 工作。
SelectPdf 确实支持 ASP.NET Core + Razor Page。可从 SelectPdf 网站下载示例。
此处的示例代码：
@page
@model SelectPdf.Samples.Pages.ConvertUrlToPdfModel
@{
Layout = "~/Pages/_Layout.cshtml";
ViewData["Title"] = "SelectPdf Free Html To Pdf Converter for .NET Core - Convert from Url to Pdf - C# / ASP.NET Core MVC6";
ViewData["Description"] = "SelectPdf Convert from Url to Pdf Sample for C# ASP.NET MVC. Pdf Library for .NET with full sample code in C# and VB.NET.";
ViewData["Keywords"] = "convert from url to pdf,pdf library,sample code,html to pdf,pdf converter";
}
<form method="post">
<article class="post type-post status-publish format-standard hentry">
<header class="entry-header">
<h1 class="entry-title">SelectPdf Free Html To Pdf Converter for .NET Core - Convert from Html to Pdf - C# / ASP.NET Core MVC6 Sample</h1>
</header>
<!-- .entry-header -->
<div class="entry-content">
<p>
This sample shows how to use SelectPdf html to pdf converter to convert an url to pdf,also setting a few properties.
</p>
<p>
Url:<br />
<input type="text" style="width: 90%;" value="https://selectpdf.com" asp-for="TxtUrl" />
</p>
<div class="col2">
Pdf Page Size:<br />
<select asp-for="DdlPageSize" asp-items="Model.PageSizes"></select>
<br />
<br />
Pdf Page Orientation:<br />
<select asp-for="DdlPageOrientation" asp-items="Model.PageOrientations"></select><br />
<br />
</div>
<div class="col2">
Web Page Width:<br />
<input type="text" style="width: 50px;" value="1024" asp-for="TxtWidth" /> px<br />
<br />
Web Page Height:<br />
<input type="text" style="width: 50px;" value="" asp-for="TxtHeight" /> px<br />
(leave empty to auto detect)<br />
<br />
</div>
<div class="col-clear"></div>
<p>
<input type="submit" name="BtnConvert" value="Create PDF" class="mybutton" />
</p>
</div>
<!-- .entry-content -->
</article>
</form>
// C# code below
using System;
using System.Collections.Generic;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.AspNetCore.Mvc.Rendering;
namespace SelectPdf.Samples.Pages
{
public class ConvertUrlToPdfModel : PageModel
{
public void OnGet()
{
DdlPageSize = "A4";
}
[BindProperty]
public string TxtUrl { get; set; }
[BindProperty]
public string DdlPageSize { get; set; }
public List<SelectListItem> PageSizes { get; } = new List<SelectListItem>
{
new SelectListItem { Value = "A1",Text = "A1" },new SelectListItem { Value = "A2",Text = "A2" },new SelectListItem { Value = "A3",Text = "A3" },new SelectListItem { Value = "A4",Text = "A4" },new SelectListItem { Value = "A5",Text = "A5" },new SelectListItem { Value = "Letter",Text = "Letter" },new SelectListItem { Value = "HalfLetter",Text = "HalfLetter" },new SelectListItem { Value = "Ledger",Text = "Ledger" },new SelectListItem { Value = "Legal",Text = "Legal" },};
[BindProperty]
public string DdlPageOrientation { get; set; }
public List<SelectListItem> PageOrientations { get; } = new List<SelectListItem>
{
new SelectListItem { Value = "Portrait",Text = "Portrait" },new SelectListItem { Value = "Landscape",Text = "Landscape" },};
[BindProperty]
public string TxtWidth { get; set; }
[BindProperty]
public string TxtHeight { get; set; }
public IActionResult OnPost()
{
// read parameters from the webpage
PdfPageSize pageSize =
(PdfPageSize)Enum.Parse(typeof(PdfPageSize),DdlPageSize,true);
PdfPageOrientation pdfOrientation =
(PdfPageOrientation)Enum.Parse(typeof(PdfPageOrientation),DdlPageOrientation,true);
int webPageWidth = 1024;
try
{
webPageWidth = System.Convert.ToInt32(TxtWidth);
}
catch { }
int webPageHeight = 0;
try
{
webPageHeight = System.Convert.ToInt32(TxtHeight);
}
catch { }
// instantiate a html to pdf converter object
HtmlToPdf converter = new HtmlToPdf();
// set converter options
converter.Options.PdfPageSize = pageSize;
converter.Options.PdfPageOrientation = pdfOrientation;
converter.Options.WebPageWidth = webPageWidth;
converter.Options.WebPageHeight = webPageHeight;
// create a new pdf document converting an url
PdfDocument doc = converter.ConvertUrl(TxtUrl);
// save pdf document
byte[] pdf = doc.Save();
// close pdf document
doc.Close();
// return resulted pdf document
FileResult fileResult = new FileContentResult(pdf,"application/pdf");
fileResult.FileDownloadName = "Document.pdf";
return fileResult;
}
}
}
我遇到了像 SelectPDF、WKHTMLTOPDF、PDFSharp 这样的免费库，但坦率地说，这些示例是 pre-asp.net 核心，无法安静地将它与 asp.net 核心 Razor Pages 集成。
我建议你可以使用客户端库。因为你提到的都是服务端库，它们都需要找到视图并转换为字符串。据我所知，似乎没有这种直接转换剃刀的方法pages 到 string。所以我建议你可以使用 jsPDF 库。
这是一个完整的工作演示：
@page
@model DetailsModel
<div id="details"> //be sure add this id...
<h1>Details</h1>
<div>
<h4>test</h4>
<hr />
<dl class="row">
<dt class="col-sm-2">
@Html.DisplayNameFor(model => model.test.Name)
</dt>
<dd class="col-sm-10">
@Html.DisplayFor(model => model.test.Name)
</dd>
</dl>
</div>
<div>
<a asp-page="./Edit" asp-route-id="@Model.test.Id">Edit</a> |
<a asp-page="./Index">Back to List</a>
</div>
</div>
<button onclick="javascript:demoFromHTML();">Generate PDF</button>
@section Scripts
{
<script src="https://cdnjs.cloudflare.com/ajax/libs/jspdf/1.3.2/jspdf.min.js"></script>
<script>
function demoFromHTML() {
var pdf = new jsPDF('p','pt','letter');
// source can be HTML-formatted string,or a reference
// to an actual DOM element from which the text will be scraped.
source = $('#details')[0];
// we support special element handlers. Register them with jQuery-style
// ID selector for either ID or node name. ("#iAmID","div","span" etc.)
// There is no support for any other type of selectors
// (class,of compound) at this time.
specialElementHandlers = {
// element with id of "bypass" - jQuery style selector
'#bypassme': function (element,renderer) {
// true = "handled elsewhere,bypass text extraction"
return true
}
};
margins = {
top: 80,bottom: 60,left: 40,width: 522
};
// all coords and widths are in jsPDF instance's declared units
// 'inches' in this case
pdf.fromHTML(
source,// HTML string or DOM elem ref.
margins.left,// x coord
margins.top,{ // y coord
'width': margins.width,// max width of content on PDF
'elementHandlers': specialElementHandlers
},function (dispose) {
// dispose: object with X,Y of the last line add to the PDF
// this allow the insertion of new lines after html
pdf.save('Test.pdf');
},margins);
}
</script>
}
您也可以查看 Syncfusion，他们有一个很棒的图书馆。
https://www.syncfusion.com/pdf-framework/net-core/pdf-library
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