CS 230 Fall 2009                                               

Assignment 9 – Files (and what went before) --  Personal Internet Radio!

100 Assignment Points

Assigned: 11/09/2009

Due: 11/16/2009 at the start of class

Pre-Lab (Do Before Lab):  Bring materials – a way to save a copy for you and a copy to turn in. Read through the whole assignment; hints and details are spelled out throughout. Plan out tasks, objects, and events needed for program.  Plan out major  pseudocode.

Main Assignment Description:

LaSalloogle Labs is developing an online radio station in which you create your own personal radio station and music is streamed to you based on what you like and don’t like (like other services already out there).  Your program is a simplification dealing with ranking songs (only)..

· The program should at start up get from a file (songs.txt) a list of songs and display them in a list box (or ComboBox).

· When the user selects a song from the song list box, the song information should be displayed in a read-only text box or in a label. (This should be done via the default event for the list box)

· When a user specifies a rating (0-5) AND selects a “Rate” button, write the rating (song and rating) to a comma-delimited text file (see below) for later tabulation (add it to those already in the file), and remove the song from the list box of songs. (DO NOT have the rating recorded immediately upon selection in case of inadvertent click).

Provide the capability to:

· Rate a song

· clear (song and rating),  and

· exit

Please set the name of the project to something other than the default name (WindowsApplication1, …). It is helpful if you use a name that identifies you as well as the assignment (e.g. yourlastname assignment 9).

Background Knowledge:

· Ratings are whole numbers

· Songs would typically include title and artist (see songs.txt file provided on Blackboard), but any format will work.

Task Details:

• We have covered procedures and functions – I recommend that you continue to use them (e.g. validation, reading from the file).
• Songs could be loaded into a List Box or a Combo Box. The commands are the same. I believe that with a larger list of songs that a list box is better for the user.
• To add a choice to a list box or combo box use: controlname.Items.Add(thechoice)
• The songs should be loaded upon the start of the program. The user should not have to do anything for them to be loaded.
• You must use the filename specified above, so I can easily test a bunch of different programs in a row. Sample files are provided on Blackboard. In the spirit of thorough testing of programs, you should try other versions of files as well.
• The only user entered value is the song rating. For validation, ensure when the rate button is selected that the song has been filled in and a valid rating has been entered.  
• The song rating  should be validated when the “rate”  button is clicked to ensure that it is a number, and is between 0 and 5 (inclusive). Don’t try to go on if bad data has been entered (display a message).  

It is recommended that the validation be done via calling a function!

• After the rate button has been successfully recorded, give the listener some kind of confirmation (e.g. a msgbox) and automatically clear the song and rating choices.
• To remove an item from a list box or combo box use: controlname.Items.Remove(thevaluetoremove)
• When you remove the song from the song listbox, that will result automatically in a change to the item selected property of the list box, triggering an event. Your event procedure needs to protect against that crashing your program (the selected item will be set to “nothing” which is a built in value – typing it in (nothing) you should see it turn blue.

• MAKE SURE YOUR PROGRAM WORKS! (i.e. gets the correct answers) - it doesn’t have to just run, it needs to run correctly!  Now that our program is branching, we need to try more examples to make sure that they work. We want all paths through the program to work correctly. Think, “what different possibilities need to be checked?”For instance, does your program do the right thing when there are user errors?

Miscellaneous:

• You must turn on Option Strict and Option Explicit
• Put YOUR NAME, e-mail address, date, and purpose of the program in comments at the beginning of the program. The purpose should be what the program is supposed to do, not the learning goals.  
• You MUST include comments that explain your program in order to get full credit.
• Name all textboxes, rich text boxes and buttons meaningfully, and use conventions for ending their names. Also, any labels referred to in code should also be named meaningfully.
• Any variables that you declare should have meaningful names – descriptive of the data that they hold.
• Make any textboxes and rich text boxes that user should never enter a value in “Read Only” (or use labels instead of textboxes!)
• Put your name on the form as a Label or as part of the form title.
• Try to use good user interface design. Make clear what user needs to do and what the answers mean.

Hand in:

• Compressed (zipped) folder with your entire project containing all files related to the project, submitted to Blackboard.  Please name the zip file something along the lines of yournameAssignment9
• Print out of your code.