In this exercise, you modify the Check Digit application from this chapter’s Apply lesson. Use Windows to make a copy of the Check Digit Solution folder. Rename the copy Check Digit Solution-Hyphens. Open the Check Digit Solution.sln file contained in the Check Digit Solution-Hyphens folder. 

a. Modify the txtIsbn_KeyPress procedure to allow the user to also enter hyphens. 

b. Before verifying the length of the ISBN entered by the user, the btnAssign_Click procedure should assign the ISBN (without any hyphens) to the strIsbn variable. Make the appropriate modifications to the procedure. 

c. When displaying the ISBN in the lblFinalIsbn control, the btnAssign_Click procedure should insert a hyphen after the third number, the fourth number, the seventh number, and the twelfth number (for example, 978-1-337-10212-4). Make the appropriate modifications to the procedure. 

d. Save the solution and then start and test the application. (If the user enters 978-1-285-86026, with or without the hyphens, the btnAssign_Click procedure should display 978-1-285-86026-8.)