How to convert TIFF to PDF in C#, VB

//get the image stream and draw frame by frame
using (var tiffImage = new PdfBitmap(docStream))
{
int frameCount = tiffImage.FrameCount;
 
for (int i = 0; i < frameCount; i++)
{
//add the page
var page = document.Pages.Add();
//Page settings
document.PageSettings.Margins.All = 0;
 
//create graphics
var g = page.Graphics;
tiffImage.ActiveFrame = i;
 
//draw tiff frame
g.DrawImage(tiffImage, 0, 0, tiffImage.PhysicalDimension.Width, tiffImage.PhysicalDimension.Height);
 
}
}