this.pdfViewer.Document.AcroForm.FlattenFormFields();

using (Stream output = File.OpenWrite("Exported.pdf"))
{
	this.pdfViewer.Save(output);
}

this.pdfViewer.Document.AcroForm.FlattenFormFields();

using (Stream output = File.OpenWrite("Exported.pdf"))
{
	PdfFormatProvider provider = new PdfFormatProvider();
	provider.Export(this.pdfViewer.Document, output);
}

var pageMarginsPropInfo = typeof(PagesLayoutManagerBase).GetField("pageMargins", System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.NonPublic);
pageMarginsPropInfo.SetValue(null, new Size(0, 0));