- How to downscale all images in a PDF
- How to generate and export certificates
- How to downscale all images in a PDF
- Add Stamp to PDF
- How to reduce PDF file size
- How do I create graphics with Icc based colors
- Highlight fields in PDF
- Add a note to PDF
- Resize PDF pages
- Verify a custom digital PDF signature
- Extract glyph boxes from PDF
- Use TrueType font collections
- Layout text with MultilineTextShape
- Merge PDF files in C# .NET
- How do I extract page destinations from bookmarks?
- Clip PDF page content in C#
- Fill PDF form
- Extract glyphs and sort by reading order
- Add bookmarks to PDF
- How to scale content of PDF
- Create rectangles with rounded corners
- Create text with decorations
- Create layers in PDF and draw on each layer
- TIFF to PDF C#
- Crop content on a PDF page
- How to embed files in a PDF document
- Remove graphics from PDF
- Change the color inside a PDF
- Import FDF into PDF
- Flatten PDF form
- Digitally sign a PDF form in C# or VB.NET
- Vector graphics in PDF
- Translate PDF page content
- Extract graphics from PDF
- Determine the content bounding box
- Search text in PDF
- Convert PDF to plain text
- Flatten Markup Annotation
- Add text field to PDF
- Extract embedded files from PDF
- Extract images from PDF
- Add a Diagonal Watermark to PDF in C#
- Fit image to PDF page
- Add simple html text to PDF
- Add multiline text to a PDF document
- Add single-line text to PDF
- Create a new digitally signed PDF document
- PDF Viewer Preferences
- Change page orientation PDF
- Split PDF pages in C# and VB.NET
- Append two or more existing PDF files
- Determine if a PDF only contains images
- Add footer to PDF
- Convert SVG to PDF
- Fill in a PDF form using MVC
- Add hyperlink to PDF
- Rotate a PDF page
- Change the formatting of a numeric field
- How to mirror PDF pages and other shapes
- Fill in a template PDF document
- How to add autosized text to PDF
- Create formfields in PDF documents
- Export FDF from PDF form
- Add a link with an internal destination to PDF
- Remove PDF security settings
- Add a link to PDF with an external destination
- How to sign and verify updates to a PDF document
- Embed TrueType font
- How to create a tiling for shapes in PDF
- EMF to PDF as vector image
- EMF to PDF as raster image
- Replace field with image
- Add a rubber stamp annotation with a custom icon
- Create a text annotation in PDF with rich text
- Read and write meta data from PDF
- Create a custom signature handler to sign and verify PDF documents
- Download and convert image to PDF
- Add barcodes to PDF
- Use multiple licenses
- Disable submit button after submitting
Read and write meta data from PDF
This article shows a sample for reading and writing meta data from PDF using C#.
What is meta data
Metadata is used for data about the document like author, creation date …. These are the PDF standard metadata. PDF also supports custom metadata. Custom metadata could hold any kind of information. For example tracking info for a business process that involves the document. Metadata consists of name-value pairs under a metadata schema. The values are of type string. This can be any kind of string, but when it is structured data, it is very common to use XML for it, where the metadata schema holds an url to the schema that describes the structure of the XML.
More info about metadata can be found:
How to read meta data
The structure for meta data in the PDF document is as follows:
- A Document has an attribute MetadataSchemas of type MetadataSchemaCollection.
- The MetadataSchemaCollection is a collection of type MetadataSchema.
- A MetadataSchema has attributes Prefix, NamespaceUri and Names.
- The MetadataSchema holds a collection of name – value pairs.
- The Names attribute contains all the names of name – value pairs that are associated to the MetadataSchema.
- With a name a corresponding value can be retrieved from the MetadataSchema.
C# code sample that reads all the meta data from a PDF document
using (FileStream inputStream = new FileStream(@"..\..\input.pdf", FileMode.Open, FileAccess.Read))
{
Document document = new Document(inputStream);
MetadataSchemaCollection metadataSchemas = document.MetadataSchemas;
Console.WriteLine($"MetadataSchemas.Count = {metadataSchemas.Count}");
foreach (MetadataSchema metadataSchema in metadataSchemas)
{
Console.WriteLine($"MetadataSchema: {metadataSchema.Prefix} --> {metadataSchema.NamespaceUri}");
foreach (string name in metadataSchema.Names)
{
string value = "unknown";
MetadataString metadataString = metadataSchema[name] as MetadataString;
if (null != metadataString)
{
value = metadataString.Value;
}
Console.WriteLine($" - name = '{name}' value = '{value}'");
}
}
}
How to write meta data
Now that you know how to read meta data from a PDF, this section will provide a code sample that shows how to write meta data to PDF
Sample custom metadata XML from DocuSign
<?xml version="1.0" encoding="UTF-8"?>
<DocuSignDocumentTemplate xmlns="http://www.docusign.net/API/3.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" canAddTabs="true">
<Header>
<Name>template</Name>
<Version>1.0</Version>
...
</Header>
<Document>
<Name>ADV_AGRMT_DOC_EX1</Name>
<Source requireInstanceDoc="true">C:\Documents and Settings\a331760\Desktop\ADV_AGRMT_DOC_EX1.pdf</Source>
<NumPages>1</NumPages>
<Size>21050</Size>
</Document>
<Recipients>
<Recipient>
...
<RoleName>ESIG_PRIMARY_OWNER</RoleName>
<RoutingOrder>1</RoutingOrder>
<Type>Signer</Type>
<RequireAccessCode>false</RequireAccessCode>
...
<Tabs>
<Tab>
<PageNumber>1</PageNumber>
<XPosition>88</XPosition>
<YPosition>492</YPosition>
<Type>SignHere</Type>
</Tab>
</Tabs>
</Recipient>
...
</Recipients>
</DocuSignDocumentTemplate>
C# sample that writes meta data to a PDF document
Document document = new Document();
document.Pages.Add(new Page(PageSize.A4));
MetadataSchema metadataSchema = document.MetadataSchemas.Add("tc", @"http://test.tallcomponents.com/testschema/");
metadataSchema.Add("Songwriter", "Johansson");
metadataSchema.Add("Songs", "<songs><song>Close to my soul</song><song>Winter is over</song></songs>");
using (FileStream outputStream = new FileStream(@"output.pdf", FileMode.Create, FileAccess.Write))
{
document.Write(outputStream);
}

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