In C# 6.0 two new features were introduced related to Exception Handling.
1. Now we can use await in a Catch and Finally block.
  1. try{
  2. do something
  3. }
  4. Catch {
  5. await Reset();
  6. }
  7. Finally{
  8. await Reset ();
  9. }
2. We can use an Exception Filter. For example:
  1. using Microsoft.VisualStudio.TestTools.UnitTesting;
  2. using System.ComponentModel;
  3. using System.Runtime.InteropServices;
  5. [TestMethod][ExpectedException(typeof(Win32Exception))]
  6. public void ExceptionFilter_DontCatchAsNativeErrorCodeIsNot42()
  7. {
  8. try
  9. {
  10. throw new Win32Exception(Marshal.GetLastWin32Error());
  11. }
  12. catch (Win32Exception exception)
  13. if (exception.NativeErrorCode == 0x00042)
  14. {
  15. // Only provided for elucidation (not required).
  16. Assert.Fail("No catch expected.");
  17. }
  18. }

The catch block now verifies that not only is the exception of type Win32Exception (or derives from it), but also verifies additional conditions; the specific value of the error code in this example.

There was no equivalent alternate way of coding exception filters prior to C# 6.0. Until now, the only approach was to catch all exceptions of a specific type, explicitly check the exception context and then re-throw the exception if the current state wasn't a valid exception-catching scenario.