Error 'System.InvalidOperationException: 'Byte[]' must not be null here.'

[evgenyshugaev]

Hello.
We are using package PdfSharp (6.2.3) with net9.0.
And some simpe code for merging image to pdf:

			var ms = new MemoryStream(content, 0, content.Length, true, publiclyVisible: true);
			var document = PdfReader.Open(ms, PdfDocumentOpenMode.Modify);
				
            for (int i = 0; i < document.PageCount; i++)
			{
					try
					{
			            // error here
                        using XGraphics gfx = XGraphics.FromPdfPage(page);

                        // ... some code

					}
					catch (Exception ex)
					{
						Logger.Log(ex, ExceptionSource.WebForm);
					}
			`}`

and we have got error for pages 12, 13, 15. Files with issue uploaded to your ftp server with name pdfsharp6-2-3-error-FromPdfPage.zip

[ThomasHoevel]

The PDF file is valid, but unusual.

PDFsharp 6.2.4 (coming 2026) will handle it correctly.

[PDFsharp-Team]

Fixed in 6.2.4.

[brianzoller]

I'm seeing a very similar issue as this one in PDFsharp 6.2.4 which has the fix.

        using var inputPdfForm = XPdfForm.FromStream(inputStream);
        for (var pageNumber = 1; pageNumber <= inputPdfForm.PageCount; pageNumber++)
        {
            inputPdfForm.PageNumber = pageNumber;
            if (inputPdfForm.Page is null)
            {
                _logger.LogWarning("Page {PageNum} is null, skipping", pageNumber);
                continue;
            }

            PdfPage newPage = outputDocument.AddPage();
            newPage.Size = PageSize.Letter;
            newPage.Orientation = inputPdfForm.Page.Width > inputPdfForm.Page.Height ? PageOrientation.Landscape : PageOrientation.Portrait;

            using (var gfx = XGraphics.FromPdfPage(newPage)) //Prepare to draw on the new page
            {
                gfx.DrawImage(inputPdfForm, new XRect(new XPoint(0.0, 0.0), new XSize(newPage.Width, newPage.Height)));
            }

[...]
        }

This fails with exception

Xunit.Sdk.XunitException
Did not expect any exception, but found System.InvalidOperationException: 'Byte[]' must not be null here.
   at PdfSharp.Diagnostics.NRT.ThrowOnNull[TResult](String message)
   at PdfSharp.Pdf.Filters.Filtering.Decode(Byte[] data, PdfItem filterItem, PdfItem decodeParms)
   at PdfSharp.Pdf.Filters.Filtering.Decode(Byte[] data, PdfItem filterItem, PdfItem decodeParms)
   at PdfSharp.Pdf.Advanced.PdfContent.Decode()
   at PdfSharp.Pdf.Advanced.PdfContent..ctor(PdfDictionary dict)
   at PdfSharp.Pdf.Advanced.PdfContents..ctor(PdfArray array)
   at PdfSharp.Pdf.PdfPage.get_Contents()
   at PdfSharp.Pdf.Advanced.PdfFormXObject..ctor(PdfDocument thisDocument, PdfImportedObjectTable importedObjectTable, XPdfForm form)
   at PdfSharp.Pdf.Advanced.PdfFormXObjectTable.GetForm(XForm form)
   at PdfSharp.Pdf.PdfPage.GetFormName(XForm form)
   at PdfSharp.Drawing.Pdf.XGraphicsPdfRenderer.GetFormName(XForm form)
   at PdfSharp.Drawing.Pdf.XGraphicsPdfRenderer.Realize(XImage image)
   at PdfSharp.Drawing.Pdf.XGraphicsPdfRenderer.DrawImage(XImage image, Double x, Double y, Double width, Double height)
   at PdfSharp.Drawing.XGraphics.DrawImage(XImage image, Double x, Double y, Double width, Double height)
   at PdfSharp.Drawing.XGraphics.DrawImage(XImage image, XRect rect)

Is this issue separate from the existing fix in 6.2.4? Is there some way to check whether XGraphics object is in a valid state to call DrawImage?

[ThomasHoevel]

Is this issue separate from the existing fix in 6.2.4?

Obviously yes, if you still get the exception.

Is there some way to check whether XGraphics object is in a valid state to call DrawImage?

Yes. But maybe no easy way.

You get an exception with a Unit Test and a specific PDF file, we only see a code snippet and do not have the PDF file.

This could be an issue similar to bug 323 discussed here and it might be fixed with current internal builds of PDFsharp, but we cannot tell.

[brianzoller]

Thank you! Would it be possible for me to access an internal build or the branch used to create such a build? Do you have an ETA for when that code may be released as a package?

[ThomasHoevel]

@brianzoller If we get a PDF that allows us to replicate the issue, then we can tell you what must be changed in version 6.2.4 to handle it.

[brianzoller]

@ThomasHoevel Unfortunately, the document contains sensitive information including DocuSign signatures. I tried redacting the PDF, but the redacted version doesn't reproduce the error.