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Pdf Library for .NET

Partial Page Conversion with Html to Pdf Converter

Select.Pdf can render only a specific section of a web page - an image, a table, a table row, a div - instead of the whole page. The section is identified by a CSS selector, set through the VisibleWebElementSelector property. The property is available on every object that drives the rendering engine:

Any selector the browser understands can be used - #invoice for an element id, .infobox for a class, table.wikitable tbody for a nested element. The first match is rendered.

Note  Note

A selector that matches nothing, or that matches an element with no size, fails the conversion with HtmlToPdfException, rather than quietly producing the whole page.

Important note  Important

VisibleWebElementId and the matching properties on the other objects are obsolete. They accept an element id only and are kept so that existing code keeps compiling: setting the id x is the same as setting the selector #x. Reading the property returns the id when the selector is a plain id, and null otherwise - a selector such as .infobox has no id to report. Use the selector property in new code.

Convert only a section of a page to pdf

The engine lifts the selected element out of the page and prints it on its own. The text stays real text - it is selectable and searchable in the produced pdf.

Note  Note

The generated document keeps the page size the converter was asked for (PdfPageSize / PdfPageCustomSize, A4 by default), so the section is rendered at the top of a normal page rather than on a sheet trimmed to its height. Margins, orientation and the header/footer bands keep working as usual. To get a document exactly as tall as the section, set PdfPageCustomSize to the size you need.

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// instantiate a html to pdf converter object
HtmlToPdf converter = new HtmlToPdf();

// render only the element matched by this css selector
converter.Options.VisibleWebElementSelector = "#invoice";

// create a new pdf document converting an url
PdfDocument doc = converter.ConvertUrl(url);

// save pdf document
doc.Save("Sample.pdf");

// close pdf document
doc.Close();
Render a page section to an image

On the image path the resulting picture is exactly as large as the selected element.

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// instantiate a html to image converter object
HtmlToImage converter = new HtmlToImage();

// specify the section that will be rendered
converter.VisibleWebElementSelector = "table.wanted";

// render the section - the png contains only that element
byte[] image = converter.ConvertUrl(url);

System.IO.File.WriteAllBytes("Section.png", image);
Place a page section into a pdf document

PdfHtmlElement renders the section and draws it at a chosen position on a page of a pdf document, keeping the text real. HtmlToImageElement does the same but draws the section as a picture, so its text is not selectable or searchable in the produced pdf.

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// create a new pdf document
PdfDocument doc = new PdfDocument();
PdfPage page = doc.AddPage();

// render only the given section of the page and draw it at (0, 0)
PdfHtmlElement section = new PdfHtmlElement(0, 0, url);
section.VisibleWebElementSelector = "#invoice";
page.Add(section);

// save pdf document
doc.Save("Sample.pdf");

// close pdf document
doc.Close();
Removing parts of a page instead

To keep the page but drop some of its parts, use HiddenWebElements, which hides the elements you name before the page is printed - see Exclude Elements from Conversion.

See Also