---
title: "Extract file attachments from PDF in C# | Nutrient .NET SDK"
canonical_url: "https://www.nutrient.io/guides/dotnet/extraction/file-attachments/"
md_url: "https://www.nutrient.io/guides/dotnet/extraction/file-attachments.md"
last_updated: "2026-05-15T19:10:04.984Z"
description: "Learn how to extract embedded file attachments from PDF documents programmatically in C# using Nutrient .NET SDK. Retrieve supporting files from your PDFs."
---

# Extract file attachments from PDFs in C#

This guide explains how to extract files from PDF documents.

PDF documents can contain files in the following ways:

- A file is embedded in the PDF document.

- A file is added to the PDF document as a file attachment annotation.

The method for extracting the file is different in each case.

## Extracting files embedded in a PDF

To extract files embedded in a PDF, follow the steps below:

1. Create a `GdPicturePDF` object.

2. Select the source document by passing its path to the `LoadFromFile` method.

3. Determine the number of embedded files with the `GetEmbeddedFileCount` method and loop through them.

4. Determine the file name by passing the index of the file to the `GetEmbeddedFileName` method.

5. Create an empty byte array where you’ll save the file data.

6. Extract the file by passing the index of the file and the empty byte object to the `ExtractEmbeddedFile` method.

7. Write the file using the standard `System.IO.Stream` class.

The example below extracts all embedded files from a PDF document:

### C#

```csharp

using GdPicturePDF gdpicturePDF = new GdPicturePDF();
// Select the source document.
gdpicturePDF.LoadFromFile(@"C:\temp\source.pdf");
// Determine the number of embedded files and loop through them.
int embeddedFileCount = gdpicturePDF.GetEmbeddedFileCount();
for (int fileIndex = 0; fileIndex < embeddedFileCount; fileIndex++)
{
    // Determine the file name.
    string fileName = gdpicturePDF.GetEmbeddedFileName(fileIndex);
    // Create an empty byte array.
    byte[] fileData = null;
    // Extract the file.
    gdpicturePDF.ExtractEmbeddedFile(fileIndex, ref fileData);
    // Write the file.
    using System.IO.Stream file = File.OpenWrite(@"C:\temp\" + fileName);
    file.Write(fileData, 0, fileData.Length);
}

```

### VB.NET

```vb

Using gdpicturePDF As GdPicturePDF = New GdPicturePDF()
    ' Select the source document.
    gdpicturePDF.LoadFromFile("C:\temp\source.pdf")
    ' Determine the number of embedded files and loop through them.
    Dim embeddedFileCount As Integer = gdpicturePDF.GetEmbeddedFileCount()

    For fileIndex = 0 To embeddedFileCount - 1
        ' Determine the file name.
        Dim fileName As String = gdpicturePDF.GetEmbeddedFileName(fileIndex)
        ' Create an empty byte array.
        Dim fileData As Byte() = Nothing
        ' Extract the file.
        gdpicturePDF.ExtractEmbeddedFile(fileIndex, fileData)
        ' Write the file.
        Dim file As Stream = File.OpenWrite("C:\temp\" & fileName)
        file.Write(fileData, 0, fileData.Length)
    Next
End Using

```

#### Used methods

- [`ExtractEmbeddedFile`](/api/gdpicture/GdPicture.NET.14.API~GdPicture14.GdPicturePDF~ExtractEmbeddedFile.html)

- [`GetEmbeddedFileCount`](/api/gdpicture/GdPicture.NET.14.API~GdPicture14.GdPicturePDF~GetEmbeddedFileCount.html)

- [`GetEmbeddedFileName`](/api/gdpicture/GdPicture.NET.14.API~GdPicture14.GdPicturePDF~GetEmbeddedFileName.html)

- [`LoadFromFile`](/api/gdpicture/GdPicture.NET.14.API~GdPicture14.GdPicturePDF~LoadFromFile.html)

#### Related topics

- [Load a file](/guides/dotnet/load-a-file.md)

- [Save a file](/guides/dotnet/save-a-file.md)

## Extracting files from file attachment annotations

To extract files from file attachment annotations, follow the steps below:

1. Create a `GdPicturePDF` object.

2. Select the source document by passing its path to the `LoadFromFile` method.

3. Determine the number of pages with the `GetPageCount` method and loop through them.

4. Determine the number of annotations on the page with the `GetAnnotationCount` method and loop through them.

5. Determine the annotation subtype passing the index of the annotation to the `GetAnnotationSubType` method.

6. If the annotation is a file attachment annotation, determine the file name by passing the index of the annotation to the `GetFileAttachmentAnnotFileName` method.

7. Create an empty byte array where you’ll save the file data.

8. Extract the file by passing the index of the annotation and the empty byte object to the `GetFileAttachmentAnnotEmbeddedFile` method.

9. Write the file using the standard `System.IO.Stream` class.

The example below extracts all files added to a PDF document as file attachment annotations:

### C#

```csharp

using GdPicturePDF gdpicturePDF = new GdPicturePDF();
// Select the source document.
gdpicturePDF.LoadFromFile(@"C:\temp\source.pdf");
// Determine the number of pages and loop through them.
int pageCount = gdpicturePDF.GetPageCount();
for (int page = 1; page <= pageCount; page++)
{
   gdpicturePDF.SelectPage(page);
   // Determine the number of annotations on the page and loop through them.
   int annotationCount = gdpicturePDF.GetAnnotationCount();
   for (int annotationIndex = 0; annotationIndex < annotationCount; annotationIndex++)
   {
        // Determine the annotation subtype.
        string annotationSubtype = gdpicturePDF.GetAnnotationSubType(annotationIndex);
        if (annotationSubtype.Equals("FileAttachment"))
        {
            // Determine the file name.
            string fileName = gdpicturePDF.GetFileAttachmentAnnotFileName(annotationIndex);
            // Create an empty byte array.
            byte[] fileData = null;
            // Extract the file.
            gdpicturePDF.GetFileAttachmentAnnotEmbeddedFile(annotationIndex, ref fileData);
            // Write the file.
            using System.IO.Stream file = File.OpenWrite(@"C:\temp\" + fileName);
            file.Write(fileData, 0, fileData.Length);
        }
   }
}

```

### VB.NET

```vb

Using gdpicturePDF As GdPicturePDF = New GdPicturePDF()
    ' Select the source document.
    gdpicturePDF.LoadFromFile("C:\temp\source.pdf")
    ' Determine the number of pages and loop through them.
    Dim pageCount As Integer = gdpicturePDF.GetPageCount()
    For page = 1 To pageCount
        gdpicturePDF.SelectPage(page)
        ' Determine the number of annotations on the page and loop through them.
        Dim annotationCount As Integer = gdpicturePDF.GetAnnotationCount()
        For annotationIndex = 0 To annotationCount - 1
            ' Determine the annotation subtype.
            Dim annotationSubtype As String = gdpicturePDF.GetAnnotationSubType(annotationIndex)
            If annotationSubtype.Equals("FileAttachment") Then
                ' Determine the file name.
                Dim fileName As String = gdpicturePDF.GetFileAttachmentAnnotFileName(annotationIndex)
                ' Create an empty byte array.
                Dim fileData As Byte() = Nothing
                ' Extract the file.
                gdpicturePDF.GetFileAttachmentAnnotEmbeddedFile(annotationIndex, fileData)
                ' Write the file.
                Dim file As Stream = File.OpenWrite("C:\temp\" & fileName)
                file.Write(fileData, 0, fileData.Length)
            End If
        Next
    Next
End Using

```

#### Used methods

- [`GetAnnotationCount`](/api/gdpicture/GdPicture.NET.14.API~GdPicture14.GdPicturePDF~GetAnnotationCount.html)

- [`GetAnnotationSubType`](/api/gdpicture/GdPicture.NET.14.API~GdPicture14.GdPicturePDF~GetAnnotationSubType.html)

- [`GetFileAttachmentAnnotEmbeddedFile`](/api/gdpicture/GdPicture.NET.14.API~GdPicture14.GdPicturePDF~GetFileAttachmentAnnotEmbeddedFile.html)

- [`GetFileAttachmentAnnotFileName`](/api/gdpicture/GdPicture.NET.14.API~GdPicture14.GdPicturePDF~GetFileAttachmentAnnotFileName.html)

- [`GetPageCount`](/api/gdpicture/GdPicture.NET.14.API~GdPicture14.GdPicturePDF~GetPageCount.html)

- [`LoadFromFile`](/api/gdpicture/GdPicture.NET.14.API~GdPicture14.GdPicturePDF~LoadFromFile.html)

- [`SelectPage`](/api/gdpicture/GdPicture.NET.14.API~GdPicture14.GdPicturePDF~SelectPage.html)

#### Related topics

- [Load a file](/guides/dotnet/load-a-file.md)

- [Save a file](/guides/dotnet/save-a-file.md)

---

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