How to hide annotations from an existing PDF document using C# and VB.NET
The Syncfusion Essential® PDF is a .NET PDF library used to create, read, and edit PDF documents. Using this library, you can hide the annotations from an existing PDF document using C# and VB.NET.
Steps to hide the annotation from an existing PDF document programmatically
- Create a new console application project.
- Install the Syncfusion.Pdf.Winforms NuGet package as a reference to your .NET Framework application from Nuget.org.
- Include the following namespaces in the Program.cs file.
C#
using Syncfusion.Pdf; using Syncfusion.Pdf.Interactive; using Syncfusion.Pdf.Parsing;
VB.NET
Imports Syncfusion.Pdf Imports Syncfusion.Pdf.Interactive Imports Syncfusion.Pdf.Parsing
- Use the following code sample to hide the annotation from an existing PDF document.
C#
//Loads the document
PdfLoadedDocument loadedDocument = new PdfLoadedDocument("../../Data/InputAnnotation.pdf");
//Gets the first page from the document
PdfLoadedPage page = loadedDocument.Pages[0] as PdfLoadedPage;
//Gets the annotation collection
PdfLoadedAnnotationCollection annotations = page.Annotations;
//Hide annotations by setting the AnnotationFlags as Hidden
foreach(var annotation in annotations)
{
if(annotation is PdfLoadedTextMarkupAnnotation)
{
PdfLoadedTextMarkupAnnotation ellipseAnnotation = annotation as PdfLoadedTextMarkupAnnotation;
ellipseAnnotation.AnnotationFlags = PdfAnnotationFlags.Hidden;
}
else if (annotation is PdfLoadedFreeTextAnnotation)
{
PdfLoadedFreeTextAnnotation ellipseAnnotation = annotation as PdfLoadedFreeTextAnnotation;
ellipseAnnotation.AnnotationFlags = PdfAnnotationFlags.Hidden;
}
else if (annotation is PdfLoadedRectangleAnnotation)
{
PdfLoadedRectangleAnnotation ellipseAnnotation = annotation as PdfLoadedRectangleAnnotation;
ellipseAnnotation.AnnotationFlags = PdfAnnotationFlags.Hidden;
}
}
//Save the PDF document
loadedDocument.Save("Sample.pdf");
//Close the document
loadedDocument.Close(true);
//This will open the PDF file and the result will be seen in the default PDF Viewer
Process.Start("Sample.pdf");
VB.NET
'Loads the document
Dim loadedDocument As PdfLoadedDocument = New PdfLoadedDocument("../../Data/InputAnnotation.pdf")
'Gets the first page from the document
Dim page As PdfLoadedPage = TryCast(loadedDocument.Pages(0), PdfLoadedPage)
'Gets the annotation collection
Dim annotations As PdfLoadedAnnotationCollection = page.Annotations
'Hide annotations by setting the AnnotationFlags as Hidden
For Each annotation In annotations
If TypeOf annotation Is PdfLoadedTextMarkupAnnotation Then
Dim ellipseAnnotation As PdfLoadedTextMarkupAnnotation = TryCast(annotation, PdfLoadedTextMarkupAnnotation)
ellipseAnnotation.AnnotationFlags = PdfAnnotationFlags.Hidden
ElseIf TypeOf annotation Is PdfLoadedFreeTextAnnotation Then
Dim ellipseAnnotation As PdfLoadedFreeTextAnnotation = TryCast(annotation, PdfLoadedFreeTextAnnotation)
ellipseAnnotation.AnnotationFlags = PdfAnnotationFlags.Hidden
ElseIf TypeOf annotation Is PdfLoadedRectangleAnnotation Then
Dim ellipseAnnotation As PdfLoadedRectangleAnnotation = TryCast(annotation, PdfLoadedRectangleAnnotation)
ellipseAnnotation.AnnotationFlags = PdfAnnotationFlags.Hidden
End If
Next
'Save the PDF document
loadedDocument.Save("Sample.pdf")
'Close the document
loadedDocument.Close(True)
'This will open the PDF file and the result will be seen in the default PDF Viewer
Process.Start("Sample.pdf")
A complete working sample can be download from AnnotationSample.zip.
Take a moment to peruse the documentation. You can find other options like adding an annotation to the PDF document, flatten annotation, removing annotation, import, and export annotation from an existing PDF document, printing annotation, and add custom stamp using the rubber stamp annotation.
Refer to this link to explore a rich set of Syncfusion Essential® PDF features.
Note:
Starting with v16.2.0.x, if you reference Syncfusion® assemblies from the trial setup or the NuGet feed, include a license key in your projects. Refer to the link to learn about generating and registering the Syncfusion® license key in your application to use the components without a trial message.
Conclusion:
I hope you enjoyed learning about how to hide annotations from an existing PDF document using C# and VB.NET.
You can refer to our Flutter PDF feature tour page to learn about its other groundbreaking features and documentation, and how to quickly get started with configuration specifications. You can also explore our Flutter PDF Flutter PDF examples to understand how to create and manipulate data.
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