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Add Underline Annotations to PDF via .NET SDK

API for adding annotations to PDF documents with .NET.

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Aspose.PDF Cloud SDK for .NET Aspose.PDF Cloud SDK for .NET

Overview

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How to append annotations to PDF documents using Cloud .NET SDK

In order to add annotations to PDF documents via Cloud .NET SDK , we’ll use Aspose.PDF Cloud .NET SDK This Cloud SDK allows you to easily build cloud-based PDF creator, editor & converter apps in C#, ASP.NET, or other .NET languages for various cloud platforms. Open NuGet package manager, search for Aspose.PDF Cloud and install. You may also use the following command from the Package Manager Console.

Package Manager Console Command


    PM> Install-Package Aspose.Pdf-Cloud
     

Steps to add annotations using .NET SDK

Aspose.PDF Cloud developers can easily load & append annotations to PDF documents in just a few lines of code.

  1. Uploads a PDF to cloud storage.
  2. Creates a green underline annotation with rich metadata.
  3. Applies it to a specific page.
  4. Handles the server response.
  5. Downloads the updated file.
 

This sample code shows adding underline annotations to PDF document


    using Aspose.Pdf.Cloud.Sdk.Model;

    namespace Annotations
    {
        public class NewUnderlineAnnotation
        {
            public static async Task Append(AnnotationsHelper helper, string documentName, int pageNumber, string outputName, string remoteFolder)
            {
                await helper.UploadFile(documentName);

                List<UnderlineAnnotation> annotations = new List<UnderlineAnnotation>
                {
                    new UnderlineAnnotation(
                        Name: "Underline_NEW_Annotation",
                        Rect: new Rectangle(100,350, 450,400),
                        Flags: new List<AnnotationFlags>() { AnnotationFlags.Default },
                        HorizontalAlignment: HorizontalAlignment.Left,
                        VerticalAlignment: VerticalAlignment.Top,
                        RichText: helper.config.NEW_UL_ANNOTATION_TEXT,
                        Subject: helper.config.NEW_UL_ANNOTATION_SUBJECT,
                        Contents: helper.config.NEW_UL_ANNOTATION_CONTENTS,
                        Title: helper.config.NEW_UL_ANNOTATION_DESCRIPTION,
                        ZIndex: 1,
                        Color: new Color(A: 0xFF, R: 0x00, G: 0xFF, B: 0x00),
                        QuadPoints: new List<Point>() {
                            new Point(X: 10, Y: 10),
                            new Point(X: 20, Y: 10),
                            new Point(X: 10, Y: 20),
                            new Point(X: 10, Y: 10)
                        },
                        Modified: "03/27/2025 00:00:00.000 AM"
                    )
                };
                AsposeResponse response = await helper.pdfApi.PostPageUnderlineAnnotationsAsync(documentName, pageNumber, annotations, folder: remoteFolder);

                if (response == null)
                    Console.WriteLine("NewUnderlineAnnotation(): Unexpected error!");
                else if (response.Code < 200 || response.Code > 299)
                    Console.WriteLine("NewUnderlineAnnotation(): Failed to append underline annotation to the document.");
                else
                {
                    Console.WriteLine("NewUnderlineAnnotation(): annotations '{0}' added to the document '{1}.", helper.config.NEW_UL_ANNOTATION_TEXT, documentName);
                    await helper.DownloadFile(documentName, outputName, "add_underline_annotation_");
                }
            }
        }
    }