.NET exception handling

Describe how exceptions are handled by the CLR?

Usually the exceptions that occur in the try are caught in the catch block. The finally is used to do all the cleaning up work. But exceptions can occur even in the finally block. By using CLR, the exception are caught even in the finally block. Also when an exception is thrown, the CLR looks for an appropriate catch filter that can handle the exception and then it executes the finally block before terminating the execution on the catch filter.      

How to throw a custom exception?     

The usual try - catch - finally - ent try format has to be followed. However, in this case, instead of using the preset exceptions from the System.Exception, you define your OwnException class and inherit Exception or ApplicationException class.

You need to define three constructors in your OwnException Class: One without parameters, other with String parameter for error message and the last one has to have one parameter as a String and other as an Inner exception object.

Example:

class OwnException : ApplicationException
{
     public OwnException() : base() {}
     public OwnException(string s) : base(s) {}
     public OwnException(string s, Exception ae) : base(s, ae) {}
}