Convert PDF to Base64 in C# using Aspose.PDF for .NET

convert-pdf-to-base64-in-csharp.md

Learn how to Convert PDF to Base64 in C# using Aspose.PDF for .NET

convert-pdf-to-base64-in-csharp_basic.cs

using Aspose.Pdf;
using Aspose.Pdf.Text;

// 1) Load the PDF
using var doc = new Document("sample_pdf.pdf");

// Optionally perform edits here, e.g., optimize, redact, secure, etc.

// 2) Save to memory
using var ms = new MemoryStream();
doc.Save(ms);
var bytes = ms.ToArray();

// 3) Convert to Base64
var base64 = Convert.ToBase64String(bytes);

Console.WriteLine(base64.Substring(0, Math.Min(base64.Length, 120)) + "...");

convert-pdf-to-base64-in-csharp_single_page.cs

using System;
using System.IO;
using Aspose.Pdf;

// Open the source PDF from a file path
using var src = new Document("sample_pdf.pdf");

// Create a new empty PDF that will contain only the selected page(s)
using var sub = new Document();

// Copy the requested page into the new document
sub.Pages.Add(src.Pages[1]);

// Save the one-page PDF to memory instead of disk
using var ms = new MemoryStream();
sub.Save(ms);

// Convert the in-memory PDF bytes to a Base64 string
var base64 = Convert.ToBase64String(ms.ToArray());

// Print a short preview of the Base64 text to the console
Console.WriteLine(base64.Substring(0, Math.Min(base64.Length, 120)) + "...");

convert-pdf-to-base64-in-csharp_with_create.cs

using System;
using System.IO;
using Aspose.Pdf;

// 1) Create a new PDF document in memory
var pdf = new Document();

// 2) Add a page and some sample content
var page = pdf.Pages.Add();
var header = new TextFragment("Hello from Aspose.PDF");
header.TextState.FontSize = 18;
header.TextState.FontStyle = FontStyles.Bold;
page.Paragraphs.Add(header);

var body = new TextFragment("This PDF was generated in memory and then converted to Base64.");
body.TextState.FontSize = 12;
page.Paragraphs.Add(body);

// 3) Save to a MemoryStream
using var ms = new MemoryStream();
pdf.Save(ms);
byte[] bytes = ms.ToArray();

// 4) Convert to Base64 string
string base64 = Convert.ToBase64String(bytes);

// 5) Optionally prepare a data URI for browsers or embed in JSON
string dataUri = $"data:application/pdf;base64,{base64}";

// Output for demo purposes
Console.WriteLine("Base64 length: " + base64.Length);
Console.WriteLine("Data URI sample (truncated): " + dataUri.Substring(0, Math.Min(dataUri.Length, 80)) + "...");

convert-pdf-to-base64-in-csharp_with_revert.cs

using System;
using System.IO;
using Aspose.Pdf;

// Read Base64 text from a file and trim extra whitespace or newlines
using System;
using System.IO;
using Aspose.Pdf;

// Read the text file
string base64 = File.ReadAllText("sample-base64.txt").Trim();

// Optional: handle data URI input like "data:application/pdf;base64,AAAA..."
// Detect and strip the prefix so only the raw Base64 remains
const string prefix = "data:application/pdf;base64,";
if (base64.StartsWith(prefix, StringComparison.OrdinalIgnoreCase))
    base64 = base64.Substring(prefix.Length);

// Decode the Base64 string into a byte array
byte[] pdfBytes = Convert.FromBase64String(base64);

// Validate by loading the bytes into Aspose.PDF; this throws if bytes are not a valid PDF
using var doc = new Document(new MemoryStream(pdfBytes));

// Persist the recovered PDF to disk
doc.Save("output.pdf");