SYSLIB0009: AuthenticationManager is not supported
The following APIs are marked obsolete, starting in .NET 5. Use of these APIs generates warning SYSLIB0009
at compile time and throws a PlatformNotSupportedException at run time.
In .NET 9 and later versions, the entire AuthenticationManager class is marked obsolete. Use of this class generates warning SYSLIB0009
at compile time.
The methods in this class either no-op or throw a PlatformNotSupportedException at run time.
Workarounds
Implement IAuthenticationModule, which has methods that were previously called by AuthenticationManager.Authenticate.
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 SYSLIB0009
// Code that uses obsolete API.
// ...
// Re-enable the warning.
#pragma warning restore SYSLIB0009
To suppress all the SYSLIB0009
warnings in your project, add a <NoWarn>
property to your project file.
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
...
<NoWarn>$(NoWarn);SYSLIB0009</NoWarn>
</PropertyGroup>
</Project>
For more information, see Suppress warnings.