Develop an application with one screen that calculates the monthly
salary of an employee. Your application should satisfy the following
requirements:
1.      Make
sure you use all of the following components: 
Label, TextBox, RadioButton, ComboBox, CheckBox, ListBox, Button, GroupBox
2.      Employee
Name: (TextBox)
3.      Employee
Grade Level: (ComboBox)
Director, Manager, Project Manager, Programmer
4.      Basic
Salary: (RadioButton)
30,000, 40,000, 50,000, 100,000