How to do it...

1. To illustrate the use of a throw expression, create a method called GetNameLength() in the Chapter1 class. All it does is check to see if the length of a name is not zero. If it is, then the method will throw an exception right there in the expression.

        public int GetNameLength(string firstName, string lastName)
        {
          return (firstName.Length + lastName.Length) > 0 ? 
            firstName.Length + lastName.Length : throw new 
            Exception("First name and last name is empty");
        }

2. To see the throw expression in action, create an instance of the Chapter1 class and call the GetNameLength() method. Pass it two blank strings as parameters.

        try
        {
          Chapter1 ch1 = new Chapter1();
          int nameLength = ch1.GetNameLength("", "");
        }
        catch (Exception ex)
        {
          WriteLine(ex.Message);
        }

3. Running your console application will then return the exception message as the output.