Fun with VB

1
Fun with VB

• CS0004
• Lecture 13

2
Administration

• Project 2 due today
• What does by midnight mean?
• Mid-term next week
• Review sheet is online
• Sample questions for exam
• Review next Monday
• Come to class with questions
• Review on Sunday?

3
Review

• Variables
• Data Types
• String, Integer, Double, Array
• If Blocks
• Select Case
• Loops
• Do While, Do Until, For Next
• Procedures and Functions

4
Whats missing?

• Fun!

Images
Sounds
Multiple Windows/Forms
5
Resources

• These are the part of the application that isnt
  code
• Images
• Sounds
• Files
• Icons

6
Resources

• This prevents you from having filespecs embedded
  in your code
• If userWins True Then
• img.Image C\my_winner.jpg
• End If
• It does so by abstracting the file using a name,
  just like an object
• If userWins True Then
• img.Image My.Resources.WinnerImage
• End If

7
Resources

• Advantages
• Not computer dependent
• When you build your project the files are
  embedded
• Much easier to make changes later
• Use the resource manager to
• Import Resources
• Change Resources
• Delete Resources

8
Resources

• Example

9
Other Uses of Resources

• Strings?
• Application name changes
• Company name changes
• Internationalization
• Use resources instead of strings
• Just replace resource files

10
What is a Window?

• A window is the same as a form
• A form is just like all the other objects we have
  dealt with
• Windows have properties
• name, visible, enable
• Windows have events
• Load
• This event is triggered when the form loads

11
Pausing Execution

• We need the program to sleep
• There is this complex notion in computers called
  threads
• You can think of each thread as a single process
• System.Threading.Thread.Sleep(2000)
• This tells the computer to sleep (ie pause) for
  2000 milliseconds (2 seconds)
• This stops all events from firing for the
  allotted time

12
Splash Screens

• These are the screens that appear while the
  program is loading

13
Splash Screens

• Use a combination of sleeping and multiple
  windows to create a splash screen
• Can use resources to display images
• To make splash screen display at the beginning
  need to change Startup Form
• Under project properties

14
Executable Code

• As a user have you had to edit code?
• You are all computer users and yet most of you
  never saw a line of code until this class
• How is this even possible?
• The code that actually runs on your computer is
  referred to as executable code
• Not human readable

15
Executable Code

• The code you write in visual basic gets converted
  into executable code the computer can understand
• Called Compiling
• Once the code is compiled it can then be ran by
  the computer and therefore the user never sees
  the code

16
Executable Code

• What if you want to send your friend your
  blackjack application
• Would your friend need Visual Basic installed?
• Of course not, this would be a real pain
• You would just send them the compiled code
• This file will have .exe extension
• Every time you run your program a new .exe file
  is generated under the bin directory of your
  project
• Send your friend this .exe file

17
Coming Attractions

• Multi-Dimensional Arrays
• Like rows and columns
• Sorting Arrays
• Various Algorithms
• File Open dialog
• Drawing Graphics
• Pie charts, bar charts
• Using the internet (Web Services)
• How to get information from the internet and use
  it
• VB in excel, word, etc.