An object, string, or class type expected
An attempt was made to pass a predefined data type into a catch block. Only data types that derive from System.Exception can be passed into a catch block.
The following sample generates CS1015:
using System; namespace x { public class b : Exception { } public class a { public static void Main() { try { } catch(int) { // CS1015, int not derived from System.Exception } } } }