Link Annotations

• 5 minutes to read

A LinkAnnotation defines a clickable region on a PDF page. When a user activates the link, the annotation executes the action assigned to its Action property. The Action property accepts the following InteractiveAction descendants:

Action class	Description
UriAction	Opens a URL in a browser.
GoToAction	Navigates to a destination in the current PDF document.
RemoteGoToAction	Navigates to a destination in another PDF file.
JavaScriptAction	Runs JavaScript code.
NamedAction	Executes a named viewer action (for instance, print or find).

Create a Link Annotation

Create a LinkAnnotation object, specify its bounds and action, and add it to the page annotation collection.

The following code snippet adds a text fragment to the page and wraps it in a link that opens a URL:

C#

FileStream fs = File.OpenRead("Demo.pdf");
var options = new LoadOptions();
PdfDocument document = new PdfDocument(fs, options);
Page page = document.Pages[0];

RectangleF textRect = new RectangleF(50,530,180,50);
page.Fragments.Add(new TextFragment {
    Text = "The DevExpress PDF Viewer",
    Location = new PointF(60, 550),
    Font = new TextFont("Arial", TextFontStyle.Regular),
    ForegroundFill = new SolidFill(PdfColor.Red)
});

LinkAnnotation linkAnnotation = new(textRect) {
    Action = new UriAction { Uri = "https://www.devexpress.com" },
    HighlightingMode = AnnotationHighlightingMode.Invert
};

page.Annotations.Add(linkAnnotation);

document.Save(new FileStream("Demo2.pdf", FileMode.Create, FileAccess.Write));

VB.NET

Dim fs As FileStream = File.OpenRead("Demo.pdf")
Dim options As New LoadOptions()
Dim document As New PdfDocument(fs, options)
Dim page As Page = document.Pages(0)

Dim textRect As New RectangleF(50, 530, 180, 50)
page.Fragments.Add(New TextFragment With {
    .Text = "The DevExpress PDF Viewer",
    .Location = New PointF(60, 550),
    .Font = New TextFont("Arial", TextFontStyle.Regular),
    .ForegroundFill = New SolidFill(PdfColor.Red)
})

Dim linkAnnotation As New LinkAnnotation(textRect) With {
    .Action = New UriAction With { .Uri = "https://www.devexpress.com" },
    .HighlightingMode = AnnotationHighlightingMode.Invert
}

page.Annotations.Add(linkAnnotation)

document.Save(New FileStream("Demo2.pdf", FileMode.Create, FileAccess.Write))

Attach a Link Annotation to Existing Text

To attach a link annotation to existing text, call the PdfDocument.FindText method, retrieve the bounding rectangle, and pass it to the LinkAnnotation constructor.

C#

using System.Drawing;
using System.IO;
using System.Linq;
using DevExpress.Docs.Pdf;

using FileStream inputStream = File.OpenRead("Document.pdf");
using PdfDocument document = new PdfDocument(inputStream);
Page page = document.Pages[0];

var searchResults = document.FindText("PDF Viewer", 0, 0).ToArray();
RectangleF textRect = searchResults[0].Groups[0].Matches[0].MatchFragment.Rectangle.BoundingBox;

LinkAnnotation linkAnnotation = new LinkAnnotation(textRect) {
    ActionTarget = new ActionTarget(new UriAction { Uri = "https://www.devexpress.com" }),
    HighlightingMode = AnnotationHighlightingMode.Invert
};
page.Annotations.Add(linkAnnotation);

Directory.CreateDirectory("output");
using FileStream outputStream = File.Create(Path.Combine("output", "Document.pdf"));
document.Save(outputStream);

VB.NET

Imports System.Drawing
Imports System.IO
Imports System.Linq
Imports DevExpress.Docs.Pdf

Module Program
    Sub Main()
        Using inputStream As FileStream = File.OpenRead("Document.pdf"), document As New PdfDocument(inputStream)
            Dim page As Page = document.Pages(0)

            Dim searchResults = document.FindText("PDF Viewer", 0, 0).ToArray()
            Dim textRect As RectangleF = searchResults(0).Groups(0).Matches(0).MatchFragment.Rectangle.BoundingBox

            Dim linkAnnotation As New LinkAnnotation(textRect) With {
                .ActionTarget = New ActionTarget(New UriAction With {.Uri = "https://www.devexpress.com"}),
                .HighlightingMode = AnnotationHighlightingMode.Invert
            }
            page.Annotations.Add(linkAnnotation)

            Directory.CreateDirectory("output")
            Using outputStream As FileStream = File.Create(Path.Combine("output", "Document.pdf"))
                document.Save(outputStream)
            End Using
        End Using
    End Sub
End Module

Create a Link to the Specific Page

Assign a GoToAction to the Action property. Use a FitDestination instance to specify the target page in the same document.

C#

using System.Drawing;
using System.IO;
using DevExpress.Docs.Pdf;

using FileStream inputStream = File.OpenRead("Document.pdf");
using PdfDocument document = new PdfDocument(inputStream);
Page page = document.Pages[0];

RectangleF textRect = new RectangleF(500, 30, 100, 50);
page.Fragments.Add(new TextFragment {
    Text = "Open 3rd Page",
    Location = new PointF(510, 50),
    Font = new TextFont("Arial", TextFontStyle.Regular),
    ForegroundFill = new SolidFill(PdfColor.Blue)
});

LinkAnnotation linkAnnotation = new LinkAnnotation(textRect) {
    ActionTarget = new ActionTarget(new GoToAction {
        Destination = new FitDestination(),
        Page = document.Pages[2]
    }),
    HighlightingMode = AnnotationHighlightingMode.Push
};
page.Annotations.Add(linkAnnotation);

Directory.CreateDirectory("output");
using FileStream outputStream = File.Create(Path.Combine("output", "Document.pdf"));
document.Save(outputStream);

VB.NET

Imports System.Drawing
Imports System.IO
Imports DevExpress.Docs.Pdf

Module Program
    Sub Main()
        Using inputStream As FileStream = File.OpenRead("Document.pdf"), document As New PdfDocument(inputStream)
            Dim page As Page = document.Pages(0)

            Dim textRect As New RectangleF(500, 30, 100, 50)
            page.Fragments.Add(New TextFragment With {
                .Text = "Open 3rd Page",
                .Location = New PointF(510, 50),
                .Font = New TextFont("Arial", TextFontStyle.Regular),
                .ForegroundFill = New SolidFill(PdfColor.Blue)
            })

            Dim linkAnnotation As New LinkAnnotation(textRect) With {
                .ActionTarget = New ActionTarget(New GoToAction With {
                    .Destination = New FitDestination(),
                    .Page = document.Pages(2)
                }),
                .HighlightingMode = AnnotationHighlightingMode.Push
            }
            page.Annotations.Add(linkAnnotation)

            Directory.CreateDirectory("output")
            Using outputStream As FileStream = File.Create(Path.Combine("output", "Document.pdf"))
                document.Save(outputStream)
            End Using
        End Using
    End Sub
End Module

Create a Link to Another PDF Document

Assign a RemoteGoToAction to the Action property to navigate to a page in a different PDF file. Set FileSpecification.FileName to the target file and OpenInNewWindow to true to display the file in a new window.

C#

using System.Drawing;
using System.IO;
using DevExpress.Docs.Pdf;

using FileStream inputStream = File.OpenRead("Document.pdf");
using PdfDocument document = new PdfDocument(inputStream);
Page page = document.Pages[0];

RectangleF textRect = new RectangleF(500, 30, 100, 50);
page.Fragments.Add(new TextFragment {
    Text = "Open Invoice",
    Location = new PointF(510, 50),
    Font = new TextFont("Arial", TextFontStyle.Regular),
    ForegroundFill = new SolidFill(PdfColor.Blue)
});

LinkAnnotation linkAnnotation = new LinkAnnotation(textRect) {
    ActionTarget = new ActionTarget(new RemoteGoToAction {
        Destination = new FitDestination(),
        PageIndex = 1,
        FileSpecification = new FileSpecification { FileName = "Invoice.pdf" },
        OpenInNewWindow = true
    }),
    HighlightingMode = AnnotationHighlightingMode.Push
};
page.Annotations.Add(linkAnnotation);

Directory.CreateDirectory("output");
using FileStream outputStream = File.Create(Path.Combine("output", "Document.pdf"));
document.Save(outputStream);

VB.NET

Imports System.Drawing
Imports System.IO
Imports DevExpress.Docs.Pdf

Module Program
    Sub Main()
        Using inputStream As FileStream = File.OpenRead("Document.pdf"), document As New PdfDocument(inputStream)
            Dim page As Page = document.Pages(0)

            Dim textRect As New RectangleF(500, 30, 100, 50)
            page.Fragments.Add(New TextFragment With {
                .Text = "Open Invoice",
                .Location = New PointF(510, 50),
                .Font = New TextFont("Arial", TextFontStyle.Regular),
                .ForegroundFill = New SolidFill(PdfColor.Blue)
            })

            Dim linkAnnotation As New LinkAnnotation(textRect) With {
                .ActionTarget = New ActionTarget(New RemoteGoToAction With {
                    .Destination = New FitDestination(),
                    .PageIndex = 1,
                    .FileSpecification = New FileSpecification With {.FileName = "Invoice.pdf"},
                    .OpenInNewWindow = True
                }),
                .HighlightingMode = AnnotationHighlightingMode.Push
            }
            page.Annotations.Add(linkAnnotation)

            Directory.CreateDirectory("output")
            Using outputStream As FileStream = File.Create(Path.Combine("output", "Document.pdf"))
                document.Save(outputStream)
            End Using
        End Using
    End Sub
End Module