Exception: ‘[character]’, hexidecimal value 0x[value], is an invalid character

Problem

When running an Excel report rendered by ExcelWriter’s ExcelTemplate object, the report will throw the following eception if the data set contains certain special characters:

Unhandled Exception: SoftArtisans.OfficeWriter.ExcelWriter.SAException: ‘[character], hexadecimal value 0x[value], is an invalid character. at SoftArtisans.OfficeWriter.ExcelWriter.ExcelTemplate.Process()

This exception occurs if:

  • Data is imported into an Excel file using ExcelWriter
  • Files are .XLSX (Office 2007) or .XLSM (Office 2007 with macros enabled)
  • Data set contains a character that is not valid in XML

Note: Support for OOXML files was introduced in OfficeWriter 4.0, so this issue only occurs in OfficeWriter 4.0-4.6.0 (ExcleWriter 7.0 – 7.6.0).

Solution

Option 1: Upgrade to OfficeWriter 4.6.1 or later (recommended)

This issue was addressed in OfficeWriter 4.6.1 (ExcelWriter 7.6.1). As of version 7.6.1, ExelWriter correctly preserves characters that are not valid in XML, so they will appear in output.

Product updates for OfficeWriter can be downloaded at www.officewriter.com/product-updates.

Note: Make sure to uninstall the old version of OfficeWriter before installing a new version.

If you are experiencing this issue with OfficeWriter for SQL Server Reporting Services and need to upgrade the server-side installation of OfficeWriter, we generally recommend upgrading the client-side installation of the OfficeWriter Designer as well.

Option 2: Scrub data of invalid XML characters

There are certain ranges of characters that are not valid XML. The XML specification has defined which ranges of characters are supported in XML files. These files cannot be written into XML files, which includes the OOXML file formats. Excel handles the special characters by encoding them before they are written to file.

Since ExcelWriter 7.0-7.6.0 does not handle these characters properly, the other solution is to remove any characters that are not valid XML, if the characters don’t need to be preserved.

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