Assembly.GetEntryAssembly() can be null

[rokmeglicbit]

An example code is using
LogManager.GetRepository(Assembly.GetEntryAssembly());

however, I get this warning:

Possible null reference argument for parameter 'repositoryAssembly' in 'ILoggerRepository LogManager.GetRepository(Assembly repositoryAssembly)'.

Is there any other way I could use log4net without a warning?

Another option is to use the frame

System.Diagnostics.StackFrame frame = new System.Diagnostics.StackFrame(1);
var method = frame.GetMethod();
Type type = method.DeclaringType;

but declaringType can also be null.

Possible null reference argument for parameter 'loggerType' in 'Type loggerType)'.

Any other solution?

[bugraskl]

You do not need to call Assembly.GetEntryAssembly() here. log4net has a parameterless overload specifically for the default repository:

var repository = LogManager.GetRepository();

The current implementation resolves the calling assembly internally (and uses log4net's fallback on platforms where caller assembly discovery is unavailable), so there is no nullable value in your code.

If you deliberately want the repository associated with a known assembly, use a compile-time-known type instead:

var repository = LogManager.GetRepository(typeof(Program).Assembly);

For ordinary logging, the usual pattern is simply:

private static readonly ILog Log = LogManager.GetLogger(typeof(MyClass));

There is no need to inspect a stack frame; that approach is less reliable because frames, methods, and declaring types can be missing or changed by optimization/inlining.

[rokmeglicbit]

Thank you.

Can this be usefull for default variable initializaton the class also?
LogManager.GetLogger(LogManager.GetRepository().Name);

[FreeAndNil]

See @bugraskl's comment below: GetLogger(string) takes a logger name, so this gives you a logger named after the repository. Use LogManager.GetLogger(typeof(MyClass)).

[bugraskl]

For a default logger field, the usual pattern is still to use the class type directly:

private static readonly ILog Log = LogManager.GetLogger(typeof(MyClass));

This is safe for static field initialization and gives the logger the class name. LogManager.GetRepository().Name is the repository name, not the current class name, so using it as the logger argument would create/use a logger with that repository name.

If you specifically want a string-based logger name, use typeof(MyClass).FullName (or another deliberate name) instead.

[rokmeglicbit]

Thank you. This way we now log things where before the logger did not.