System.IO.IOException: I/O error when opening file 'C:\WINDOWS\FONTS\MSYH.TTC'.

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Last Updated: 23 Jan 2025 16:21 by gerry

gerry

Created on: 17 Jan 2025 12:10

Category: Telerik Document Processing

Type: Bug Report

System.IO.IOException: I/O error when opening file 'C:\WINDOWS\FONTS\MSYH.TTC'.

As Ghiath reported in the forum thread, I am seeing this same error.

I am using RadFixedDocument and am generating a PdfFormatProvider. As Ghiath mentioned it will work fine (weeks, months) and then it seems the the font file is locked and it cannot export.

System.IO.IOException: I/O error when opening file 'C:\WINDOWS\FONTS\MSYH.TTC'.

System.Web.HttpUnhandledException (0x80004005): Exception of type 'System.Web.HttpUnhandledException' was thrown. ---> System.IO.IOException: I/O error when opening file 'C:\WINDOWS\FONTS\MSYH.TTC'.
   at MS.Internal.FontCache.FileMapping.OpenFile(String fileName)
   at MS.Internal.FontCache.FontSource.GetUnmanagedStream()
   at System.Windows.Media.GlyphTypeface.ComputeSubset(ICollection`1 glyphs)
   at Telerik.Windows.Documents.Fixed.Model.Fonts.CidType2Font.ComputeSubset(IEnumerable`1 usedCharacters)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.Fonts.FontStream.CopyPropertiesFromOverride(IPdfExportContext context, FontBase font)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.Fonts.FontStream.CopyPropertiesFrom(IPdfExportContext context, FontBase font)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.Fonts.FontDescriptor.CreateFontFile(IPdfExportContext context, FontBase font)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.Fonts.FontDescriptor.ExportFontFile(IPdfExportContext context, FontBase font)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.Fonts.FontDescriptor.CopyPropertiesFrom(IPdfExportContext context, FontBase font)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.Fonts.CidFontObject.CopyPropertiesFromOverride(IPdfExportContext context, FontBase font)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.Fonts.CidFontObject.CopyPropertiesFrom(IPdfExportContext context, FontBase font)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Elements.Fonts.Type0FontObject.CopyPropertiesFromOverride(IPdfExportContext context, FontBase font)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Export.PdfExporter.WriteFontsFromContext(PdfWriter writer, IPdfExportContext context)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Export.PdfExporter.Export(IRadFixedDocumentExportContext context, Stream output)
   at Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.PdfFormatProvider.ExportOverride(RadFixedDocument document, Stream output)
   at Telerik.Windows.Documents.Common.FormatProviders.FormatProviderBase`1.Export(T document, Stream output)

It will throw the exception on the line where it is doing the export. The document is typically a multi-page document with images, etc. As I mentioned it might work fine for weeks and then once it fails the only solution is to recycle the web service.

2 comments

gerry

Posted on: 23 Jan 2025 16:21

Hello--I did not expect that you would be able to reproduce the problem with a simple test. As has been shown by multiple people the error occurs randomly.

I would ask that you look at the source code for PdfFormatProvider Export to see how it is failing on trying to open the font. Under what circumstances could the font file open fail?

Thank you,

Gerry

ADMIN

Dess | Tech Support Engineer, Principal

Posted on: 17 Jan 2025 12:57

Hi, Gerry,

I am sorry to hear that you are facing any difficulties with the RadFixedDocument when using RadPdfProcessing.

Following the provided information, I was unable to reproduce the issue you are facing. Please refer to the attached gif file illustrating the behavior on my end with the specified version. I have attached my sample project. Please give it a try and see how it works on your end. Am I missing something? Could you please specify the exact steps how to reproduce the problem? Feel free to modify the project in a way to reproduce the experienced issue and get back to me with it so I can investigate the precise case. Thank you in advance.

Off topic, I would like to provide some useful details to avoid any confusion.

Telerik Document Processing Libraries offer PdfFormatProvider which makes it easy to import/export a RadFixedDocument from/to PDF format, preserving the entire document structure and formatting. It is available for:

RadWordsProcessing: The PdfFormatProvider class of RadWordsProcessing is located in the Telerik.Windows.Documents.Flow.FormatProviders.Pdf namespace. RadFlowDocument supports only the export option to PDF format. Importing a PDF document to RadFlowDocument is not supported.

RadSpreadProcessing: The PdfFormatProvider class of RadSpreadProcessing is located in the Telerik.Windows.Documents.Spreadsheet.FormatProviders.Pdf namespace. The Workbook supports only the export to PDF format. Importing a PDF document to Workbook is not supported.

RadPdfProcessing: The PdfFormatProvider class of RadPdfProcessing is located in the Telerik.Windows.Documents.Fixed.FormatProviders.Pdf namespace.

On the other hand, RadRichTextBox from the UI for WPF suite also offers a PdfFormatProvider class located in the Telerik.Windows.Documents.FormatProviders.Pdf namespace.

I am looking forward to your reply.

Regards,
Dess | Tech Support Engineer, Principal
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Attached Files:

1676125pdferror.zip