Add underline text annotations to PDF documents via .NET SDK

API for adding underline text annotations to PDF documents using As[pse.PDF Cloud .NET SDK.

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Aspose.PDF Cloud SDK for .NET

Overview

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    How to insert underline text 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: 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

    
    public static async Task AddUnderlineAnnotation()
    {
        const string localPdfDocument = @"C:\Samples\sample.pdf";
        const string storageFileName = "sample.pdf";
        const string localFolder = @"C:\\Samples";
        const string resultFileName = "output_add_ul_annotation.pdf";
        const int pageNumber = 1;

        // Get your AppSid and AppSecret from https://dashboard.aspose.cloud (free registration required).            
        var pdfApi = new PdfApi(AppSecret, AppSid);

        var filesOnStorage = await pdfApi.GetFilesListAsync("");
        if (filesOnStorage.Value.All(f => f.Name != storageFileName))
        {
            using var file = File.OpenRead(localPdfDocument);
            var uploadResult = await pdfApi.UploadFileAsync(storageFileName, file);
            Console.WriteLine(uploadResult.Uploaded[0]);
        }
    
        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:                       "NEW UNDERLINE ANNOTATION 2",
                Subject:                        "Underline Box Subject 2",
                Contents:                       "Underline annotation sample contents 2",
                Title:                          "This is an underline annotation 2",
                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 pdfApi.PostPageUnderlineAnnotationsAsync(storageFileName, pageNumber, annotations);
    
        if (response == null)
            Console.WriteLine("AddUnderlineAnnotation(): Unexpected error!");
        else if (response.Code < 200 || response.Code > 299)
            Console.WriteLine("AddUnderlineAnnotation(): Failed to append underline annotation to the document.");
        else
        {
            await (await pdfApi.DownloadFileAsync(storageFileName))
                .CopyToAsync(File.Create(Path.Combine(localFolder, resultFileName)));
            Console.WriteLine("NewUnderlineAnnotation(): annotation added to the document '{0}.", resultFileName);
        }
    }