itext7: InvalidCastException: Unable to cast object of type iText.Html2pdf.Attach.Impl.Layout.HtmlPageBreak to type iText.Layout.Element.IBlockElement
Question
Using itext7 (7.2.0) AND itext7.pdfhtml (4.0.0) AND.Net Core 5.0
Converting itext5 report to itext7
Getting the error, when forcing a page break using html style 'page-break-before: always;'
public FileResult PrintHtmlToPDFPageBreak() { StringBuilder sbBody = new StringBuilder(); sbBody.Append("<html>"); sbBody.Append("<body>"); sbBody.Append("<p>This is first page</p>"); sbBody.Append("<div style='page-break-before: always;'></div>"); sbBody.Append("<p>This is second page</p>"); sbBody.Append("</body>"); sbBody.Append("</html>"); string htmlContent = sbBody.ToString(); bool isPortrait = true; string reportTitle = "Testing iText7 in.Net5"; //generate the byte array for the Pdf byte[] pdfContent = null; //Create a System.IO.MemoryStream object using (MemoryStream memoryStream = new MemoryStream()) { //Initialize PDF writer PdfWriter pdfWriter = new PdfWriter(memoryStream); //Initialize PDF document PdfDocument pdfDocument = new PdfDocument(pdfWriter); //Initialize document Document document = (isPortrait? new Document(pdfDocument, PageSize.LETTER): new Document(pdfDocument, PageSize.LETTER.Rotate())); var headerHeight = String.IsNullOrEmpty(reportTitle)? 70f: 120f; document.SetMargins(headerHeight, 10f, 56f, 10f); //top, right, bottom, left #region HTML to PDF //Convert to Elements ConverterProperties converterProperties = new ConverterProperties(); IList<IElement> elements = HtmlConverter.ConvertToElements(htmlContent, converterProperties); foreach (var element in elements) document.Add((IBlockElement)element); #endregion //Close the Document document.Close(); pdfContent = memoryStream.ToArray(); //Close the MemoryStream memoryStream.Close(); } //return the byte array in the form of FileContentResult for browser download var fileName = "ConvertHtmlToPDF.pdf"; return File(pdfContent, System.Net.Mime.MediaTypeNames.Application.Pdf, fileName); }
2 answers
solution1
0 2022-01-18 20:46:27
You haven't attached the stacktrace but I am pretty sure the problem is in these two lines:
foreach (var element in elements)
document.Add((IBlockElement)element);
You are just casting without checking whether the cast is legitimate. Just process the case when an element is an instance of AreaBreak .
solution2
0 2022-01-20 19:39:21
Thank you Alexey your solution worked.
Old code: foreach (var element in elements) document.Add((IBlockElement)element);
New code: foreach (var element in elements) { if (element.GetType().Name == "HtmlPageBreak") document.Add(new AreaBreak(AreaBreakType.NEXT_PAGE)); else document.Add((IBlockElement)element); }
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