CSCI 220
Programming With Visual Basic

Lecture 9: Modules, Multiple forms

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Modules
  Separate files on disk
  Like the code part of a form.  No objects attached.
  Are saved on disk with a .BAS extension
  Contain
     Record definitions (see below)
     GLOBAL variable declarations
     Global procedures
  Used for
     Declaration of Global variables
       Use GLOBAL keyword in place of DIM
       Can be used only in general area of a module
       Otherwise used just like DIM
     Creation of global procedures
       Can be called from any form, any procedure in
       project
       just like a new command
     Can be used to store library of useful subprograms (EG
     Printing related)
  Created by choosing New Module from File menu or hitting
  New Module button.
  
  Scope Map:

       
General procedures
  Created in general area of  forms or modules
     In forms, makes a form - level procedure
     in module, makes a global procedure
  Can be called from within code - New command
  Syntax: Sub ProcedureName (Parameters)
     Creates a new section of the general area
     Code can be written here
  Parameters
     "Instant" local variable(s)
     Don't have to be declared (!)
     Calling a procedure - Simply use its name in code.

Multiple forms
  Creation:  New Form on File menu or New form button
  Useful Methods
     Show
       Syntax:  FormName.Show [modal]
          FormName is the name of a form you have created in
          the project
       Example: Second.Show 1
          Loads Second into memory if it's not there, shows
          it to user
       Modal switch
          If you end the show method with a 1, the form will
          be modal
            New form gets focus
            Next code activated is in the form_load
            procedure of the second form
            Control reverts to original form after second
            is closed
            You usually will want to do this
          If you do not put a 1 at the end,
            New form shows up, does not get the focus
            control of program moves on to next line of
            code in first form
       Hide
          Syntax: FormName.Hide
          Example: Second.Hide
            Hides the named form.
            Control reverts back to procedure that showed
            the form
          Warning!  Don't hide ALL the forms in a project!
     Startup form
       One form must be designated as startup form
       By default this will be the first one created
       To change, use the Project dialog under the Options
       menu

Your Project- The quiz maker

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Create a Module
Declare a new record type called QuestType.  QuestType
should have the following fields:
  Question (string, 50 characters)
  AnsA  (string, 50 characters)
  AnsB  (string, 50 characters)
  AnsC  (string, 50 characters)
  Correct  (string, 1 character)
Create a Global QuestType array called Quest.  It should
have three elements (1-3)
Go to the form.  In the  general area, create an integer
variable called QuestNum
Form_Load
  Initialize the Quest array.  Example:
     Quest(1).Question = "What is your name?"
     Quest(1).AnsA = "Arthur, King of the Britons
     Quest(1).AnsB = "Roger the shrubber"
     Quest(1).AnsC = "Galahad the Chaste"
     Quest(1).Correct = "A"
  Initialize the value of QuestNum to one
  Call the question writing subprogram (that doesn't yet
  exist)
In each label, call the CheckAns procedure, giving it an
"A", "B", or "C" parameter
WriteQuest
  Using the current value of QuestNum to choose the array's
  index, fill the labels with the appropriate values from
  the Quest array
  Put this code in a general procedure of the form
CheckAns
  Create a general-level procedure called CheckAns
  Give it a parameter called guess
  If the user's guess is the same as the current value of
  the Correct field of Quest, then
     increment the question number
     If new Question number is less than 4 Call the
     WriteQuest procedure
  If the user was wrong,
     Send a messagebox telling the user so.
  After all three questions are answered completely, call a
  modal form that will congratulate the user
  End the program.
                          Have Fun!