How Can I Merge Multiple Dynamically Generated PDFs Using iTextSharp?

Merging Multiple Dynamically Generated PDF Files: An iTextSharp Approach

Context:
This question pertains to merging multiple PDF files that are dynamically generated in real-time. The goal is to merge these files for printing purposes.

Solution:
To merge multiple PDF files using iTextSharp, there are two primary approaches:

1. PdfCopy Class
If the objective is to merge pages in their original format, while preserving content and interactive annotations, the PdfCopy class should be employed. A sample using PdfCopy is provided below:

// Assuming pdf is a List<byte[]> containing in-memory PDF documents
using (MemoryStream ms = new MemoryStream())
{
    using (Document document = new Document())
    {
        using (PdfCopy copy = new PdfCopy(document, ms))
        {
            document.Open();
            for (int i = 0; i < pdf.Count; ++i)
            {
                PdfReader reader = new PdfReader(pdf[i]);
                int n = reader.NumberOfPages;
                for (int page = 0; page < n; )
                {
                    copy.AddPage(copy.GetImportedPage(reader, ++page));
                }
            }
        }
    }
    mergedPdf = ms.ToArray();
}

2. PdfWriter Class
Alternatively, if the goal is to integrate pages from source documents into a new document, customizing the general format and disregarding interactive annotations, the PdfWriter class should be utilized. This class imports pages from other PDF documents but discard their interactive features.

Additional Considerations:

• PdfCopyFields: This class is used to merge the fields of different forms, specifically avoiding issues with form fields encountered when concatenating forms using PdfCopy. It has higher memory requirements.
• PdfSmartCopy: Similar to PdfCopy, it can detect redundant content but requires more memory and CPU resources.

The solution should be chosen based on the specific requirements of the project.

The above is the detailed content of How Can I Merge Multiple Dynamically Generated PDFs Using iTextSharp?. For more information, please follow other related articles on the PHP Chinese website!