Besides text and graphics, PDF files can contain entire files inside them as attachments. This makes the exchange of sets of documents much easier and more reliable. Spire.PDF allows you to attach files in two ways:
- Document Level Attachment: A file attached to a PDF at the document level won't appear on a page, but can only be viewed in the "Attachments" panel of a PDF reader.
- Annotation Attachment: A file will be added to a specific position of a page. Annotation attachments are shown as a paper clip icon on the page; reviewers can double-click the icon to open the file.
This article demonstrates how to add or remove these two types of attachments in a PDF document in C# and VB.NET using Spire.PDF for .NET.
- Add an Attachment to PDF in C# and VB.NET
- Add an Annotation Attachment to PDF in C# and VB.NET
- Remove Attachments from PDF in C# and VB.NET
- Remove Annotation Attachments from PDF in C# and VB.NET
Install Spire.PDF for .NET
To begin with, you need to add the DLL files included in the Spire.PDF for.NET package as references in your .NET project. The DLLs files can be either downloaded from this link or installed via NuGet.
PM> Install-Package Spire.PDF
Add an Attachment to PDF in C# and VB.NET
Adding an attachment to the "Attachments" panel can be easily done by using PdfDocument.Attachments.Add() method. The following are the detailed steps.
- Create a PdfDocument object.
- Load a PDF document using PdfDocument.LoadFromFile() method.
- Create a PdfAttachment object based on an external file.
- Add the attachment to PDF using PdfDocument.Attachments.Add() method.
- Save the document to another PDF file using PdfDocument.SaveToFile() method.
- C#
- VB.NET
using Spire.Pdf;
using Spire.Pdf.Attachments;
namespace AttachFilesToPDF
{
class Program
{
static void Main(string[] args)
{
//Create a PdfDocument object
PdfDocument doc = new PdfDocument();
//Load a sample PDF file
doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\Sample.pdf");
//Create a PdfAttachment object based on an external file
PdfAttachment attachment = new PdfAttachment("C:\\Users\\Administrator\\Desktop\\Data.xlsx");
//Add the attachment to PDF
doc.Attachments.Add(attachment);
//Save to file
doc.SaveToFile("Attachment.pdf");
}
}
}
Add an Annotation Attachment to PDF in C# and VB.NET
An annotation attachment can be found in the "Attachments" panel as well as on a specific page. Below are the steps to add an annotation attachment to PDF using Spire.PDF for .NET.
- Create a PdfDocument object.
- Load a PDF document using PdfDocument.LoadFromFile() method.
- Get a specific page to add annotation through PdfDocument.Pages[] property.
- Create a PdfAttachmentAnnotation object based on an external file.
- Add the annotation attachment to the page using PdfPageBase.AnnotationsWidget.Add() method.
- Save the document to another PDF file using PdfDocument.SaveToFile() method.
- C#
- VB.NET
using Spire.Pdf;
using Spire.Pdf.Annotations;
using Spire.Pdf.Graphics;
using System;
using System.Drawing;
using System.IO;
namespace AnnotationAttachment
{
class Program
{
static void Main(string[] args)
{
//Create a PdfDocument object
PdfDocument doc = new PdfDocument();
//Load a sample PDF file
doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\Sample.pdf");
//Get a specific page
PdfPageBase page = doc.Pages[0];
//Draw a label on PDF
String label = "Here is the report:";
PdfTrueTypeFont font = new PdfTrueTypeFont(new Font("Arial", 13f, FontStyle.Bold), true);
float x = 35;
float y = doc.Pages[0].ActualSize.Height - 220;
page.Canvas.DrawString(label, font, PdfBrushes.Red, x, y);
//Create a PdfAttachmentAnnotation object based on an external file
String filePath = "C:\\Users\\Administrator\\Desktop\\Report.pptx";
byte[] data = File.ReadAllBytes(filePath);
SizeF size = font.MeasureString(label);
RectangleF bounds = new RectangleF((float)(x + size.Width + 5), (float)y, 10, 15);
PdfAttachmentAnnotation annotation = new PdfAttachmentAnnotation(bounds, "Report.docx", data);
annotation.Color = Color.Purple;
annotation.Flags = PdfAnnotationFlags.Default;
annotation.Icon = PdfAttachmentIcon.Graph;
annotation.Text = "Click here to open the file";
//Add the attachment annotation to PDF
page.AnnotationsWidget.Add(annotation);
//Save to file
doc.SaveToFile("Annotation.pdf");
}
}
}
Remove Attachments from PDF in C# and VB.NET
The attachments of a PDF document can be accessed by the PdfDocument.Attachments property, and can be removed by using RemoveAt() method or Clear() method of the PdfAttachmentCollection object. The detailed steps are as follows.
- Create a PdfDocument object.
- Load a PDF document using PdfDocument.LoadFromFile() method.
- Get the attachment collection from the document through PdfDocument.Attachments property.
- Remove a specific attachment using PdfAttachmentCollection.RemoveAt() method. To remove all attachments at once, use PdfAttachmentCollection.Clear() method.
- Save the document to another PDF file using PdfDocument.SaveToFile() method.
- C#
- VB.NET
using Spire.Pdf;
using Spire.Pdf.Attachments;
namespace RemoveAttachments
{
class Program
{
static void Main(string[] args)
{
//Create a PdfDocument object
PdfDocument doc = new PdfDocument();
//Load a PDF file
doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\Attachment.pdf");
//Get attachment collection
PdfAttachmentCollection attachments = doc.Attachments;
//Remove a specific attachment
attachments.RemoveAt(0);
//Remove all attachments
//attachments.Clear();
//save to file
doc.SaveToFile("DeleteAttachments.pdf");
}
}
}
Remove Annotation Attachments from PDF in C# and VB.NET
Annotation is a page-based element. To get all annotations from a document, we must traverse through the pages and get the annotations from each page. Then determine if a certain annotation is an annotation attachment. Lastly, remove the annotation attachment from the annotation collection using Remove() method. The following are the detailed steps.
- Create a PdfDocument object.
- Load a PDF document using PdfDocument.LoadFromFile() method.
- Loop through the pages in the document, and get the annotation collection from a specific page through PdfDocument.Pages[].AnnotationsWidget property.
- Determine if an annotation is an instance of PdfAttachmentAnnotationWidget. If yes, remove the annotation attachment using PdfAnnotationCollection.Remove() method.
- Save the document to another PDF file using PdfDocument.SaveToFile() method.
- C#
- VB.NET
using Spire.Pdf;
using Spire.Pdf.Annotations;
namespace RemoveAnnotationAttachments
{
class Program
{
static void Main(string[] args)
{
//Create a PdfDocument object
PdfDocument doc = new PdfDocument();
//Load a PDF file
doc.LoadFromFile("C:\\Users\\Administrator\\Desktop\\Annotation.pdf");
//Loop through the pages
for (int i = 0; i < doc.Pages.Count; i++)
{
//Get the annotation collection
PdfAnnotationCollection annotationCollection = doc.Pages[i].AnnotationsWidget;
//Loop through the annotations
for (int j = 0; j < annotationCollection.Count; j++)
{
//Determine if an annotation is an instance of PdfAttachmentAnnotationWidget
if (annotationCollection[j] is PdfAttachmentAnnotationWidget)
{
//Remove the annotation attachment
annotationCollection.Remove((PdfAnnotation)annotationCollection[j]);
}
}
}
//Save to file
doc.SaveToFile("DeleteAnnotationAttachments.pdf");
}
}
}
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