Answer:   Yes, Custom Exception class is nothing but a user defined class which is derived from System Exception class. Below are the steps, Custom class can be derived from System Exception class. By Creating a constructor of custom class with error message parameter and we can pass it to the base class (System Exception class). Then throw and catch custom exception message in try-catch block in code wherever it is required.

Answer:   Yes we can create a custom exception in .NET.

To create a custom exception, we have two different options -

1. Create the object of a predefined Exception class where we need to pass the error message as a parameter to its constructor and then throw that object so that whenever the exception occurs the given error message gets displayed.
2. Define a new class of type exception and throw that class object by creating it.