title: Combining PDFs with PDFSharp losing form fields
body: <p>I am attempting to concatenate two created PDF files to a new PDF using PDFSharp and this code (which I found <a href="http://www.pdfsharp.net/wiki/ConcatenateDocuments-sample.ashx" rel="noreferrer">here</a>):</p>
  
  <pre><code>        // Open the output document
          PdfDocument outputDocument = new PdfDocument();
          // Iterate files
          foreach (string file in files)
          {
              // Open the document to import pages from it.
              PdfDocument inputDocument = PdfReader.Open(file, PdfDocumentOpenMode.Import);
  
              // Iterate pages
              int count = inputDocument.PageCount;
              for (int idx = 0; idx &lt; count; idx++)
              {
                  // Get the page from the external document...
                  PdfPage page = inputDocument.Pages[idx];
                  // ...and add it to the output document.
                  outputDocument.AddPage(page);
              }
          }
          // Save the document...
          string filename = Path.Combine(this.tempFolder, "MyPDF.pdf");
          outputDocument.Save(filename);
  </code></pre>
  
  <p>The second PDF has form fields which I fill out, also using PDFSharp.  The issue I am running into is that when combined into a new PDF, the form fields show up blank.</p>
  
  <p>I have opened up the second PDF after it is created and saved, and the form fields show up with the text just fine.  </p>
  
  <p>Am I missing something, or does PDFSharp have some sort of bug in regards to this issue?  It seems to me that if I can open and view the PDF just fine, there shouldn't be any problems with combining them.</p>
  
  <p>Thanks in advance for your help!</p>