What is meant by Exception Filter in error handling context?

Exception Filter in C# is a construct that allows you to specify a condition under which a catch block will be executed. This extends exception handling capabilities by allowing you to catch exceptions only if a certain logical condition is met.

The syntax looks like this:

try
{
    // code
}
catch (Exception ex) when (ex is ArgumentNullException)
{
    // handle only ArgumentNullException
}

The advantage of Exception Filter is that the condition is checked before entering the catch block, and if it is not met, the exception continues to propagate further. This is useful for more precise and efficient error handling without the need to write nested conditions inside catch.

Additionally, Exception Filter allows you to avoid catching an exception if the condition is not met, which improves readability and control over error handling.