Improvement on Exception Handling in C# 6.0

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.

try{
 do something
}
Catch {
 await Reset();
}
Finally{
 await Reset ();
}

2. We can use an Exception Filter. For example: 

using Microsoft.VisualStudio.TestTools.UnitTesting;
using System.ComponentModel;
using System.Runtime.InteropServices;

 [TestMethod][ExpectedException(typeof(Win32Exception))]
public void ExceptionFilter_DontCatchAsNativeErrorCodeIsNot42()
{
  try
  {
    throw new Win32Exception(Marshal.GetLastWin32Error());
  }
  catch (Win32Exception exception)
    if (exception.NativeErrorCode == 0x00042)
  {
    // Only provided for elucidation (not required).
    Assert.Fail("No catch expected.");
  }
}

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.