"Content can not be added to a PdfImportedPage." error - itext

Question

I am trying to download and merges multiple pdf files by using ITextSharp.
It used to working before but I being got an "Content can not be added to a PdfImportedPage." error message on the line:
importedPage = writer.GetImportedPage(reader, currentPageIndex);
The full code is below, any help will be very appreciated.
private string MergeDocuments(IList<string> fileUrls, string fileName)
{
var reportFolder = this.ReportFolder + "\\";
using (MemoryStream output = new MemoryStream())
{
Document document = new Document();
try
{
// Initialize pdf writer
PdfWriter writer = PdfWriter.GetInstance(document, output);
// Open document to write
document.Open();
PdfContentByte content = writer.DirectContent;
PdfImportedPage importedPage;
// Iterate through all pdf documents
foreach (var url in fileUrls)
{
// Create pdf reader
using (PdfReader reader = new PdfReader(new Uri(url)))
{
int numberOfPages = reader.NumberOfPages;
// Iterate through all pages
for (int currentPageIndex = 1; currentPageIndex <= numberOfPages; currentPageIndex++)
{
// Determine page size for the current page
document.SetPageSize( reader.GetPageSizeWithRotation(currentPageIndex) );
// Create page
document.NewPage();
importedPage = writer.GetImportedPage(reader, currentPageIndex);
content.AddTemplate(importedPage, 1f, 0, 0, 1f, 0, 0);
}
}
}
}
catch (Exception exception)
{
throw new Exception("Error occured", exception);
}
File.WriteAllBytes(reportFolder + fileName + ".pdf", output.GetBuffer());
}
return "Reports/" + fileName + ".pdf";
}
When I try the following code, I get a null pointer exception in the addDocument() method:
using (MemoryStream output = new MemoryStream()) {
Document document = new Document();
document.Open();
PdfCopy copy = new PdfSmartCopy(document, output);
foreach (var url in fileUrls) {
using (WebClient client = new WebClient()) {
var byteArray = client.DownloadData(url);
PdfReader reader = new PdfReader(byteArray);
copy.AddDocument(reader);
reader.Close();
}
}
}

Answer 1

I found the problem, the document object should be closed before writing memory stream to file.
Just added document.Close() as below.
document.Close();
File.WriteAllBytes(reportFolder + fileName + ".pdf", output.GetBuffer());