Thêm Văn Bản vào Đầu Trang của PDF qua .NET SDK

    using Aspose.Pdf.Cloud.Sdk.Api;
    using Aspose.Pdf.Cloud.Sdk.Model;

    namespace Headers
    {
        public class HeadersAddText
        {
            public static async Task Append(string documentName, string outputName, string headerText, int startPage, int endPage, string localFolder, string remoteFolder)
            {
		// Get your AppSid and AppSecret from https://dashboard.aspose.cloud (free registration required). 
		pdfApi = new PdfApi(AppSecret, AppSid);

                using (var file = File.OpenRead(Path.Combine(localFolder, documentName)))
		{ // Upload the local PDF to cloud storage folder name.
                    FilesUploadResult uploadResponse = await pdfApi.UploadFileAsync(Path.Combine(remoteFolder, documentName), documentName);
                    Console.WriteLine(uploadResponse.Uploaded[0]);
                }

                // Create new Text Header with input parameters for the PDF on cloud storage.
                TextHeader header = new TextHeader(
                    Background: true,
                    LeftMargin: 1,
                    RightMargin: 2,
                    HorizontalAlignment: HorizontalAlignment.Center,
                    Opacity: 1,
                    Rotate: Rotation.None,
                    RotateAngle: 15,
                    XIndent: 0,
                    YIndent: 0,
                    Zoom: 1,
                    Value: headerText
                );

                // Append new Text Header in the PDF on cloud storage.
                AsposeResponse response = await pdfApi.PostDocumentTextHeaderAsync(documentName, header, startPage, endPage, folder: remoteFolder);

                // Checks the response and logs the result.
                if (response == null)
                    Console.WriteLine("HeadersAddText(): Unexpected error!");
                else if (response.Code < 200 || response.Code > 299)
                    Console.WriteLine("HeadersAddText(): Failed to append text header to the document.");
                else
                { // Downloads the updated file for local use.
                    Console.WriteLine("HeadersAddText(): text header '{0}' successfully appended to the document '{1}'.", headerText, documentName);
                    Stream stream = pdfApi.DownloadFile(Path.Combine(remoteFolder, documentName));
                    using var fileStream = File.Create(Path.Combine(localFolder, "append_text_headerr_" + outputName));
                    stream.Position = 0;
                    await stream.CopyToAsync(fileStream);
                    Console.WriteLine("HeadersAddText(): File '{0}' successfully downloaded.", "append_text_header_" + outputName);
                }
            }
        }
    }