Many developers are not aware that according to CLR it is perfectly OK to throw exceptions which are NOT derived from System.Exception: Exceptions such as DateTime, Int64 and String. Although languages such as C# do not allows programmers to throw these types of exceptions it should still be possible to catch non-CLS compliant exceptions using a catch block.

Pre to CLR version 2.0, the only way to catch non-CLS compliant exceptions was to introduce a catch block with no Exception section:

try

{

   // Some code here which might

   // throw non-CLS compilant exception

}

catch (Exception ex)

{

   // Here we will be catching any

   // CLS compliant type of exceptions

}

catch

{

   // Here we will be catching any

   // non-CLS compliant exceptions...

   // Note that, this block on its own

   // is capable of catching both compliant

   // and non-compinat exceptions

}

In version 2.0 of CLR, any non-CLS compliant exception is automatically wrapped up by System.Runtime.CompilerServices.RuntimeWrappedException class which inherits from the Exception class. This class has a property which is set to the actual object which was thrown.

It is still possible to tell CLR not to wrap up the non-CLS compliant exceptions with the RuntimeWrappedException class. This is done using an attribute which affects the whole assembly:

[assembly: RuntimeCompatibility(WrapNonExceptionThrows = false)]