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SYSLIB0038: SerializationFormat.Binary is obsolete

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SerializationFormat.Binary is marked as obsolete, starting in .NET 7. Using this API in code generates warning SYSLIB0038 at compile time.

Workaround

If your code uses SerializationFormat.Binary, switch to using SerializationFormat.Xml or use another method of serialization.

Otherwise, you can set the Switch.System.Data.AllowUnsafeSerializationFormatBinary AppContext switch. This switch lets you opt in to allowing the use of SerializationFormat.Binary, so that code can work as before. However, this switch will be removed in .NET 8. For information about setting the switch, see AppContext for library consumers.

Suppress a warning

If you must use the obsolete APIs, you can suppress the warning in code or in your project file.

To suppress only a single violation, add preprocessor directives to your source file to disable and then re-enable the warning.

// Disable the warning.
#pragma warning disable SYSLIB0038

// Code that uses obsolete API.
// ...

// Re-enable the warning.
#pragma warning restore SYSLIB0038

To suppress all the SYSLIB0038 warnings in your project, add a <NoWarn> property to your project file.

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
   ...
   <NoWarn>$(NoWarn);SYSLIB0038</NoWarn>
  </PropertyGroup>
</Project>

For more information, see Suppress warnings.

See also