Value cannot be null. Parameter name: elementId in PDFsharp

Question

I am working on Export to PDF funtionality using C# and PDFSharp. I am getting this error:

Value cannot be null.
Parameter name: elementId

The error is on this line : PdfDocument document = PdfGenerator.GeneratePdf(htmlcontenttbl.ToString(), PdfSharp.PageSize.A4, 30);

Here's the whole method:

public bool ExportPdf(string htmlcontenttbl)
    {
        Response.ClearContent();
        Response.ClearHeaders();

        Response.Buffer = true;
        Response.ContentType = "application/octet-stream";
        Response.AddHeader("Content-Disposition", "attachment;filename=Myfile.pdf");
        //Response.AddHeader("Content-Disposition", "inline;filename=file.pdf");
        //Response.AppendHeader("Content-Disposition", "attachment; filename=Myfile.pdf");
        Response.Charset = "";
        StringWriter sw = new StringWriter();
        HtmlTextWriter htw = new HtmlTextWriter(sw);

        PdfDocument document = PdfGenerator.GeneratePdf(htmlcontenttbl.ToString(), PdfSharp.PageSize.A4, 30);
        var config = new PdfGenerateConfig();
        config.PageOrientation = PageOrientation.Landscape;
        config.PageSize = PageSize.A4;
        config.MarginBottom = 30;
        config.MarginTop = 30;
        //PdfDocument document = PdfGenerator.GeneratePdf(htmlcontenttbl, config);

        byte[] bytes = null;
        using (MemoryStream stream = new MemoryStream())
        {
            document.Save(stream, true);
            bytes = stream.ToArray();
        }

        //var path1 = Server.MapPath("~/Images/" + DateTime.Now.TimeOfDay.Ticks + "result.pdf");
        //System.IO.File.WriteAllBytes(path1, bytes);
        //Response.TransmitFile(path1, 0, bytes.Length);
        //Response.OutputStream.Write(bytes, 0, bytes.Length);

        Response.BinaryWrite(bytes);
        Response.Flush();
        Response.End();

        return true;
    }

A stack trace would really help, there is no parameter named elementId. — Ben Hoffman, Sep 13 '17 at 13:55
`ScrollToElement` is the only place in that project that throws this exception: https://github.com/ArthurHub/HTML-Renderer/search?utf8=%E2%9C%93&q=elementId&type= But no idea from where it came and why the parameter was `null` **or empty**. — Tim Schmelter, Sep 13 '17 at 14:13
Perhaps also https://github.com/ArthurHub/HTML-Renderer/blob/cc3b5c221b192a950d3d53b561ac01049668e239/Source/HtmlRenderer/Core/HtmlContainerInt.cs @TimSchmelter? — mjwills, Sep 13 '17 at 14:16
@User_2235 does the issue occur if `htmlcontenttbl` has all of the links (`a` tags) removed? — mjwills, Sep 13 '17 at 14:18
@mjwills: you're right. I guess it's [this line](https://github.com/ArthurHub/HTML-Renderer/search?utf8=%E2%9C%93&q=var+anchorRect+%3D+container.GetElementRectangle%28link.AnchorId%29%3B&type=) where the `AnchorId` is null or empty, this code is reachable from `PdfGenerator.GeneratePdf` — Tim Schmelter, Sep 13 '17 at 14:18
@mjwills thank you , i removed blank anchor tag and error is gone :) — User_2235, Sep 14 '17 at 04:25
The title is wrong - this is not a problem of PDFsharp, it is a problem of PdfGenerator. — I liked the old Stack Overflow, Sep 14 '17 at 09:45

score 2 · Accepted Answer · answered Sep 14 '17 at 04:58

2

That exception can occur if you have a blank anchor tag.

It is likely ultimately being generated from here.

You should remove the blank anchor tag.

answered Sep 14 '17 at 04:58

mjwills

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What is considered a "blank anchor tag"? I have a few containing icons, nbsp and various other elements but the rendering still fails. – Alen Siljak Jul 03 '19 at 11:39
`` is an anchor tag @AlenSiljak. – mjwills Jul 03 '19 at 11:55
Thanks, I'm aware of that but, as I've asked earlier, what is a "blank anchor tag" that breaks the renderer? I've got no blank anchor tags and the renderer still throws this exception. – Alen Siljak Jul 03 '19 at 13:03
Looking at the code (https://github.com/ArthurHub/HTML-Renderer/blob/cc3b5c221b192a950d3d53b561ac01049668e239/Source/HtmlRenderer/Core/HtmlContainerInt.cs#L619) I am going to guess one without an `id` (it has been almost two year since I've looked at this stuff). If you add `id`s to your ``s does it work? Alternatively, it may be one without a `href` as per https://github.com/ArthurHub/HTML-Renderer/blob/e0a2d1702aae5a4f267cc60d847c2c64c1a5b0bc/Source/HtmlRenderer/Core/Entities/LinkElementData.cs#L83 . – mjwills Jul 03 '19 at 13:15
Do you have any `` tags with no `href` or where the `href` is just `#` @AlenSiljak? – mjwills Jul 03 '19 at 13:23
thanks for the pointers! Yes, there are a few without text (just icons) and a few with # in href, due to use of Bootstrap 3. And, of course, no a element has an id. :) I'll try to experiment a bit and see what works. – Alen Siljak Jul 03 '19 at 13:28
@AlenSiljak, do you remember what ended up working? – Lukas Apr 14 '22 at 13:31
@Lukas, I think I removed all the annotations but it is hard to even remember the context now. Sorry! – Alen Siljak Apr 15 '22 at 16:33

Value cannot be null. Parameter name: elementId in PDFsharp

1 Answers1