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SYSLIB0024: Creating and unloading AppDomains is not supported and throws an exception

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The AppDomain.CreateDomain(String) and AppDomain.Unload(AppDomain) methods are marked as obsolete, starting in .NET 6. Using them in code generates warning SYSLIB0024 at compile time and throws an exception at run time.

Workarounds

None.

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 SYSLIB0024

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

// Re-enable the warning.
#pragma warning restore SYSLIB0024

To suppress all the SYSLIB0024 warnings in your project, add a <NoWarn> property to your project file.

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
   ...
   <NoWarn>$(NoWarn);SYSLIB0024</NoWarn>
  </PropertyGroup>
</Project>

For more information, see Suppress warnings.