Upgrading an (old) .NET application to .NET core turned into a learning experience when we got the following error message after the upgrade was done:
System.NotSupportedException : No data is available for encoding 1252. For information on defining a custom encoding, see the documentation for the Encoding.RegisterProvider method.
TLDR; The application was using an older Windows-1252 text encoding causing the error above when trying to use this in .NET Core which doesn’t support this encoding out-of-the-box.
Introduction to Text Encodings
Text encoding is a method used to convert text data into a format that can be easily processed by computers. Computers inherently understand numbers, not characters, so text encoding maps characters to numerical values. This process ensures that text data can be stored, transmitted, and interpreted correctly across different systems and platforms.
There are various text encodings, each designed to support different sets of characters. Some common encodings include:
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ASCII: Supports basic English characters.
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UTF-8: A versatile encoding that supports a wide range of characters from different languages.
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ISO-8859-1: Also known as Latin-1, supports Western European languages.
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Windows-1252: A superset of ISO-8859-1, commonly used in Windows environments.
The error: System.NotSupportedException: No data is available for encoding 1252
When working with .NET Core, you might encounter the error message: System.NotSupportedException: No data is available for encoding 1252. This error occurs because .NET Core does not include support for certain legacy encodings, such as Windows-1252, by default.
How to fix the error in .NET Core
To resolve this issue, you need to register the CodePagesEncodingProvider from the System.Text.Encoding.CodePages package. This package provides support for various code pages, including Windows-1252.
Here are the steps to fix the error:
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Install the System.Text.Encoding.CodePages Package: Open your project in Visual Studio or your preferred IDE and run the following command in the Package Manager Console:
dotnet add package System.Text.Encoding.CodePages -
Register the CodePagesEncodingProvider: In your application's startup code, register the
CodePagesEncodingProviderto enable support for the required encoding. Add the following code:
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Use the Encoding: Now, you can use the Windows-1252 encoding in your application without encountering the
System.NotSupportedExceptionerror. For example:
By following these steps, you can ensure that your .NET Core application supports the Windows-1252 encoding and avoid the System.NotSupportedException error.
More information
How to use character encoding classes in .NET - .NET | Microsoft Learn
CodePagesEncodingProvider Class (System.Text) | Microsoft Learn
NuGet Gallery | System.Text.Encoding.CodePages 9.0.2
https://www.nuget.org/packages/System.Text.Encoding.CodePages/