Working with the VB IDE

1
Working with the VB IDE
2
Running a Program

• Clicking thestart tool begins the program
• The break tool pauses a program in
  mid-execution
• The end tool terminates a program

3
The Forms Editor

• Like the Program Editor, the Forms Editor allows
  the user to modify the properties of forms, the
  sort of object that may be placed on a form and
  the location, properties and size of these
  objects.
• Most of these commands are highly intuitive and
  do not need much in the way of instruction.
• There are, however, a few additional commands in
  the Forms Editor that are less intuitive.

4
Grouping Objects

• On the form several objects can be selected at
  the same time. Do this by clicking on the
  desired objects while holding the Shift Key down.
• Here the last command
• selected was
• cmdcompute.

5
Resizing Objects

• Once several objects have been selected they may
  be gang adjusted by using the format menu
• One of the options permits resizing all selected
  objects to match the last one selected.

6
Other Commands

• Dragging all tagged objects without disturbing
  their relative locations.
• Changing justification of all text.
• Changing Font and size of all text.

• Changing the visibility of all tagged objects
• Changing the spacing (vertical, horizontal or
  both) of all tagged objects.
• Aligning all tagged objects.

7
To Learn More...

• Use the search term Format Command in the help
  system to get more detailed data.
• (note Format is such a common term that you
  must limit your search.)

8
The Program Editor

• Visual Basic (VB) supports a text editor (not a
  word processor) that permits the writing and
  modification of program code.
• The editor is one of two sub-windows that appears
  in the Workspace. The other is the Forms window.
• Many of the commands used in the editor are like
  those used in word processors, but there are
  differences.

9
Entering the Editor

• The editor is normally entered by double
  clicking on an Event Producing Object in the
  workspace.
• The result is a code window which opens with the
  subroutine describing that event as the focus.

10
Line Completion Help (1)

• When a line is being entered, the editor will
  make suggestions.
• When changing the caption on the button
  cmdthingie the editor presents suggestions when
  you add the dot.

11
Line Completion Help (2)

• I actually typed
• cmdthingie.capstart?
• (no capitals, only part of the word caption, no
  spaces at all and no closing quote. The ?
  represents the .)
• The editor did the rest.

12
Line Completion Help (3)

• When I typed a syntactically incorrect line, the
  line turned red, and a notice box was posted as
  soon as I struck the key or moved the cursor
  to a different line.

13
Line Completion Help (4)

• When I completed the line by typing the ) the
  line turned black again and was correctly spaced.
• Note I had typed no spaces.

14
Line Completion Help (5)

• If I had typed
• cmdthingee.
• The editor would not have provided any help
  since I had no existing data object named
  cmdthingee.

15
Line Completion Help (6)

• If I had completed the line anyhow and run the
  program, only then would the system be able to
  find this more complex syntactical error.

16
The Helpful Program Editor

• The Program Editor will correctly capitalize the
  names of existing data objects and legally
  spelled system commands. If you misspell one of
  them things remain in lower case.
• The Program Editor will suggest and complete the
  spelling of properties of data objects. It will
  insert appropriate spaces and complete the lines
  of correctly entered command lines.

17
The Long and the Short of It

• Some lines of code that are too long to fit
  neatly on a printed line
• These lines can be entered on multiple lines
• Some are so short that they need only a few
  characters to print
• One line can hold multiple statements

18
One statement on multiple lines

• Dim strThing As String
• strThing "This is text that " _
• is too long to fit on one line.
• The underscore _ character on the first line
  indicates continuation
• the ampersand character concatenates

19
One statement on multiple lines

• Dim sngVolume as Single, _
• sngRadius as Single, sngHeight _
• as Single
• sngVolume 3.14159 sngRadius _
• 2 sngHeight
• (You can place the underscore wherever a space
  may go, except within a quotation.)

20
Multiple statements on one line

• Dim intRed As Byte, intBlue As Byte
• intRed 3 intBlue 4
• Note the two commands on the second line
  separated by the colon character. This
  would work just as if the two commands were put
  on two separate lines. Use whatever makes the
  program read more easily.

21
Option Explicit

• To force VB to require all variables be defined,
  first click on the option sub-option of the
  tools command.

22
Option Explicit

• Then be sure to check the box require variable
  declaration on the revealed option menu.

23
Option Explicit

• You can, equivalently, simply type option
  explicit at the top of the code

24
Some Common Controls
25
The Command Control

• The command control is one of the most important
  tools in the toolbox
• Double clicking on the command button icon will
  install a command button on the working form

26
Adding a Command Button

• The command buttons are named, by default
  Command1, Command2, etc.
• They may be moved or changed in size using the
  mouse

27
Properties of Command Buttons

• Each command button has several properties.
  govern the buttons appearance and behavior
• The most important are the (name) and the caption
• (name) is how a programmer can refer to the
  button in VB code
• caption is the text a user will see displayed
  inside the button

28
Highlighting a Property

• When you highlight a property, its definition
  appears below the properties window

29
Names and Captions

• Clicking on the (name) property lets us name it
  cmdstop, (note the name starts with cmd)
• Changing the caption to Stop gives the user an
  idea as to the buttons function

30
Programming Convention

• Good practice in Visual Basic suggests that we
  should name all objects in a program with names
  that indicate their function
• These names are invariant during a programs
  execution and are seen only by programmers
• Command buttons names should begin with the
  prefix cmd
• Names should begin with the prefix for the given
  object type, and should contain only letters and
  numbers
• Captions are used to convey information to the
  user
• They can change as the program runs
• They may contain any letters, numbers, spaces,
  etc.

31
Entering Event Code

• Double clicking on the cmdstop button itself,
  causes the Code window to open
• The VB commands the define the buttons function
  go here
• The End command terminates the VB program

32
The Label Control

• The label control is an object with 37 named
  Properties.
• You can adjust its size and position with the
  mouse.
• You can change its (name) its caption and
  visibility using the Properties window.

33
Label Control Properties
34
Using Labels

• The label control is usable only for output
• It cannot accept input from the user
• Its size, shape, color, visibility and the form
  of the information presented can be controlled
• By editing its properties
• By writing VB code to change its properties
• Labels can be sized and moved using the mouse.

35
A Program Using a Label
36
Using a Label

• When program execution begins, the system starts
  as in A, when the cmdby button is pressed the
  system goes to B
• Repeated pressing of the cmdby button bounces the
  system between the two states

37
Programming Convention

• Labels should be given a (name) that begins with
  lbl.
• The Caption property of a label may be anything
  that makes sense one or more words or symbols.
• Caption is displayed for the user
• (name) is only accessible to the programmer
• The Visible property may be either True or False
• If false, the label is not displayed

38
The Text Box Control

• Labels are designed to be used for output
• Command buttons can accept input from the user,
  but only of a limited nature
• The text box control allows the user input data

39
Text Box Properties

• The text property contains the string of text
  displayed by the text box
• Unlike labels, by default this text can be edited
  by the user at runtime
• The proper prefix for text box names is txt