PDFsharp & MigraDoc Foundation

// 1. Create PdfDocuments pdfDoc1 and pdfDoc2
// 2. Create a PdfPage pdfPage1
// 3. Add pdfPage1 to pdfDoc1
// 4. Add pdfPage1 to pdfDoc2

// 1. Create PdfDocuments pdfDoc1 and pdfDoc2
// 2. Create a PdfPage pdfPage1
// 2a. Copy pdfPage1 to a new PdfPage pdfPage2
// 3. Add pdfPage1 to pdfDoc1
// 4. Add pdfPage2 to pdfDoc2

// 1. Create PdfDocuments pdfDoc1 and pdfDoc2
// 2. Create a PdfPage pdfPage1
// 3. Add pdfPage1 to pdfDoc1
// 4. Save the pdfDoc1 (with its one page) to MemoryStream ms1
// 5. Open ms1 as a PdfDocument and create a PdfPage pdfPage2 from it
// 6. Add pdfPage2 to pdfDoc2

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' VB.NET
''''''''''''''''''''''''''

Dim pdfDoc1 As New PdfDocument
Dim pdfDoc2 As New PdfDocument
Dim pdfPage1 As New PdfPage

' Design / add info to your page
pdfDoc1.AddPage(pdfPage1)

Using ms1 As New MemoryStream
     pdfDoc1.Save(ms1)
     pdfDoc2.AddPage(PdfReader.Open(ms1, PdfDocumentOpenMode.Import).Pages(0))
End Using

' Now both pdfDoc1 and pdfDoc2 have the contents of pdfPage1
' You can save each file to the file system when ready
pdfDoc1.Save("file1.pdf")
pdfDoc2.Save("file2.pdf")

////////////////////////
// C# (Untested)
////////////////////////

PdfDocument pdfDoc1 = new PdfDocument();
PdfDocument pdfDoc2 = new PdfDocument();
PdfPage pdfPage1 = new PdfPage();

// Design / add info to your page
pdfDoc1.AddPage(pdfPage1);

using (MemoryStream ms1 = new MemoryStream())
{
     pdfDoc1.Save(ms1);
     pdfDoc2.AddPage(PdfReader.Open(ms1, PdfDocumentOpenMode.Import).Pages[0]);
}

// Now both pdfDoc1 and pdfDoc2 have the contents of pdfPage1
// You can save each file to the file system when ready
pdfDoc1.Save("file1.pdf");
pdfDoc2.Save("file2.pdf");

string doc1 = @"C:\doc1.pdf";
string doc2 = @"C:\doc2.pdf";

// variable to hold page contents
CSequence contents;

// create 1st document and page
var d1 = new PdfDocument(doc1);
var page = d1.AddPage();

// you'd have to create a method to add contents to page
// refer to http://www.pdfsharp.net/wiki/HelloWorld-sample.ashx for example
AddContentToPage(page);

// close document for content to write to page
d1.Close();

// reopen 1st document to get page contents
var doc = PdfReader.Open(doc1, PdfDocumentOpenMode.Modify);
// grab page's contents
contents = ContentReader.ReadContent(doc.Pages[0]);
doc.Close();

// repeat the below 3 lines to add same content to different pdf documents
var d2 = new PdfDocument(doc2);
d2.AddPage().Contents.ReplaceContent(contents);
d2.Close();