How to load PDF document from Base64 string using C# and VB.NET?

using Syncfusion.Pdf;
using Syncfusion.Pdf.Graphics;
using Syncfusion.Pdf.Parsing;
using System.Drawing;

Imports Syncfusion.Pdf
Imports Syncfusion.Pdf.Graphics
Imports Syncfusion.Pdf.Parsing
Imports System.Drawing

//Read the base64 text from the text file
StreamReader reader = new StreamReader(@"../../Data/Base64_String.txt");
string base64String = reader.ReadToEnd();
reader.Close();
 
//Get bytes from the base64 string 
byte[] byteArray = System.Convert.FromBase64String(base64String);
 
//Load PDF document
PdfLoadedDocument loadedDocument = new PdfLoadedDocument(byteArray);
 
//Get the first page from the document
PdfLoadedPage page = loadedDocument.Pages[0] as PdfLoadedPage;
 
//Create PDF graphics for the page
PdfGraphics graphics = page.Graphics;
 
//Use the system installed font
PdfFont font = new PdfStandardFont(PdfFontFamily.Courier, 20);
 
//Draw the text
graphics.DrawString("Hello World!!!", font, PdfBrushes.Black, new PointF(0, 0));
 
//Save the PDF document to the memory stream
MemoryStream stream = new MemoryStream();
loadedDocument.Save(stream);
 
//Close the document
loadedDocument.Close(true);
 
//Convert the saved PDF document to Base64 string
string base64 = Convert.ToBase64String(stream.ToArray());
 
//Write the base64 string to a text file
File.WriteAllText("Test.txt", base64);

'Read the base64 text from the text file 
Dim reader As StreamReader = New StreamReader("../../Data/Base64_String.txt")
Dim base64String As String = reader.ReadToEnd()
reader.Close()
 
'Get bytes from base64 string 
Dim byteArray As Byte() = System.Convert.FromBase64String(base64String)
 
'Load PDF document 
Dim loadedDocument As PdfLoadedDocument = New PdfLoadedDocument(byteArray)
 
'Get the first page from the document 
Dim page As PdfLoadedPage = TryCast(loadedDocument.Pages(0), PdfLoadedPage)
 
'Create PDF graphics for the page
Dim graphics As PdfGraphics = page.Graphics
 
'Use the system installed font 
Dim font As PdfFont = New PdfStandardFont(PdfFontFamily.Courier, 20)
 
'Draw the text 
graphics.DrawString("Hello World!!!", font, PdfBrushes.Black, New PointF(0, 0))
 
'Save the PDF document to the memory stream
Dim stream As MemoryStream = New MemoryStream()
loadedDocument.Save(stream)
 
'Close the document 
loadedDocument.Close(True)
 
'Convert the saved PDF document to Base64 string 
Dim base64 As String = Convert.ToBase64String(stream.ToArray())
 
'Write the base64 string to a text file
File.WriteAllText("Test.txt", base64)