When using XML 2.0 filter an error message occurs when generating initial preview in Trados Studio: Object reference not set to an instance of an object.

Article Number:000019668 | Last Updated:8/10/2023 11:14 AM

Scope/Environment

Trados Studio 2022, Trados Studio 2021, XML-2.0-based file type containing XSLT-based preview

Symptoms/Context

When using an XML-2.0-based file type that contains an XSLT preview in a Trados Studio project and testing the preview by selecting "Click here to generate initial preview", the following error message appears:

<ErrorMessage>Object reference not set to an instance of an object.</ErrorMessage>
<Exception>
    <Type>System.NullReferenceException, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</Type>
    <HelpLink />
    <Source>Sdl.FileTypeSupport.Filters.Xml_2</Source>
    <HResult>-2147467261</HResult>
    <StackTrace><![CDATA[   at Sdl.FileTypeSupport.Filters.Xml.Preview.Common.CommonPreviewTransformationParts.TweakHtmlHead(HtmlDocument document)
   at Sdl.FileTypeSupport.Filters.Xml.Preview.Common.CommonPreviewTransformationParts.ModifyPreviewHtml(String inputPath, String outputPath, InsersectHandlingMode intersectHandlingMode, Encoding encoding)
   at Sdl.FileTypeSupport.Filters.Xml.Preview.PreviewFileTweakerService.PrepareAndWriteOutputHtml(INativeOutputFileProperties outputFileProperties)
   at Sdl.FileTypeSupport.Filters.Xml.Preview.XmlPreviewFileTweaker`1.Tweak(INativeOutputFileProperties outputFileProperties)
   at Sdl.FileTypeSupport.Framework.Core.Utilities.NativeApi.AbstractFilePostTweaker.TweakFilePostWriting(INativeOutputFileProperties outputFileProperties)
   at Sdl.FileTypeSupport.Framework.Integration.FileGenerator.ExecuteTweakers(PostGenerationMessageReporterAdapter messageAdapter)
   at Sdl.FileTypeSupport.Framework.Integration.FileGenerator.RunPostWritingOperations()
   at Sdl.FileTypeSupport.Framework.Integration.FileGenerator.FileComplete()
   at Sdl.FileTypeSupport.Framework.Integration.AbstractBilingualProcessorContainer.FileComplete()
   at Sdl.FileTypeSupport.Framework.Integration.MultiFileConverter.FileComplete()
   at Sdl.FileTypeSupport.Framework.BilingualApi.AbstractBilingualContentProcessor.FileComplete()
   at Sdl.FileTypeSupport.Framework.Integration.AbstractBilingualProcessorContainer.FileComplete()
   at Sdl.FileTypeSupport.Bilingual.Tmfc.TmfcReaderImpl.vv_Visit(TmfcReaderImpl* , FrameworkFileContainerField* field)
   at FrameworkFileContainerField.vv_AcceptFrameworkVisitor(FrameworkFileContainerField* , FrameworkFieldVisitor* visitor)
   at Sdl.FileTypeSupport.Bilingual.Tmfc.TmfcReaderImpl.vv_VisitStartEndField(TmfcReaderImpl* , StartEndField* startEnd)
   at Sdl.FileTypeSupport.Bilingual.Tmfc.TmfcReaderImpl.b_VisitNext(TmfcReaderImpl* )
   at Sdl.FileTypeSupport.Bilingual.Tmfc.TmfcReader.ParseNext()
   at Sdl.FileTypeSupport.Framework.Integration.FileExtractor.ParseNext()
   at Sdl.FileTypeSupport.Framework.Integration.MultiFileConverter.ParseNext()
   at Sdl.FileTypeSupport.Framework.Integration.MultiFileConverter.Parse()
   at Sdl.TranslationStudio.Editor.Previews.GeneratePreviewJobRequest.CreatePreviewFile(IFileTypeManager fm, IAbstractGenerator generator, GenerateType generateType)
   at Sdl.TranslationStudio.Editor.Previews.GeneratePreviewJobRequest.Execute(IJobExecutionContext context)
   at Sdl.Desktop.Platform.Implementation.Services.JobExecuter.Execute(JobData jobData)
   at Sdl.Desktop.Platform.Implementation.ResourceLoggingInternalCommandExecuter`1.ExecuteWithResourceLogging(TCommandData commandData, String message)
   at Sdl.Desktop.Platform.Implementation.Services.Job._worker_DoWork(Object sender, DoWorkEventArgs e)
   at System.ComponentModel.BackgroundWorker.OnDoWork(DoWorkEventArgs e)
   at System.ComponentModel.BackgroundWorker.WorkerThreadStart(Object argument)]]></StackTrace>
</Exception>

Resolution

Check whether the XSLT used in the XML preview does simply generate an HTML file with the structure:

<html>
  <body>
  ...
  </body>
</html>

instead of

<html>
  <head>
  ...
  </head>
  <body>
  ...
  </body>
</html>

The absence of the <head></head> element from the generated HTML output leads to the error message.
Make sure to fix the XSLT accordingly.

Root Cause

It seems that the XML 2.0 filter of Studio 2021/2022 needs to insert the following code into the <head></head> element:

<meta http-equiv="X-UA-Compatible" content="IE=edge"><meta charset="utf-8"><meta name="generator" content="Sdl.FileTypeSupport.Filters.Xml_2 2.5.10.0">

Reference

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