Catch multiple exceptions at once?

Question

It is discouraged to simply catch System.Exception. Instead, only the "known" exceptions should be caught.

Now, this sometimes leads to unnecce

Answer 1

Exception filters are now available in c# 6+. You can do

try
{
       WebId = new Guid(queryString["web"]);
}
catch (Exception ex) when(ex is FormatException || ex is OverflowException)
{
     WebId = Guid.Empty;
}

In C# 7.0+, you can combine this with pattern matching too

try
{
   await Task.WaitAll(tasks);
}
catch (Exception ex) when( ex is AggregateException ae &&
                           ae.InnerExceptions.Count > tasks.Count/2)
{
   //More than half of the tasks failed maybe..? 
}