Chapter 3: Customizing a Form and Writing Simple Programs Chapter 4: First Steps in Building the Use

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Chapter 3 Customizing a Form and Writing Simple
Programs Chapter 4 First Steps in Building the
User Interface
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Program Design Process

• 1. Define the problem to be solved.
• 2. Work with the user to determine the inputs
  available to solve the problem and the required
  outputs.
• 3. Determine how the user wants to enter,
  retrieve, and inspect information.
• 4. (a) Design the user interface using forms and
  controls and (b) set the properties.

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Program Design Process (cont.)

• 5. Test this interface by asking the user to
  determine if it is acceptable. Return to Step 4
  if the interface is not acceptable.
• 6. Write the code (event procedures and modules)
  for the design.
• 7. Test the completed design by asking the user
  if it is acceptable. If not, return to Step 4 or
  6, depending on the type of design problem.

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Rapid Application Design (RAD)
User and Developer
Developer Only
Define
Code
Modify
Test
Review
Acceptance
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Focus on Three Key Programming Steps

• 1. Layout the user interface (forms, controls).
• 2. Set properties.
• 3. Write the code (including modules).

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Example Clock

• Add a label
• Change its properties
• Caption Time will go here
• Name lblTime
• Alignment 2 - Center
• Add a command button
• Change its properties
• Caption Time
• Name cmdTime
• Write Code
• lblTime.Caption Now
• Save and run project

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VB Working Environment Toolbox

• Add a control to a form
• Click on the control within the Toolbox
• Click the active form
• Drag to size the control
• Add a control (Alternate method)(Not for framed
  objects)
• Double click the control (appears in the middle
  of the form)
• Move and size the control as appropriate

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VB Working EnvironmentForm Window

• Where you create the windows, dialog boxes, and
  controls in your application.
• Draw and view controls on a form using the
  toolbox.

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VB Working Environment Project Explorer Window

• Displays a hierarchical list of the projects and
  all of the items contained in a project (e.g.
  forms and modules)
• Use icons to quickly view form and view the code
  window

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VB Working Environment Properties Window

• Lists the design-time characteristics for
  selected objects.
• Click object to make it active
• Caption or Text
• Name the object -- follow the control naming
  convention
• Set other properties...

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VB Working Environment Form Layout Window

• Position the form where you want it to appear at
  run time.
• Show the form relative to the display dimensions.

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VB Working Environment Code Window

• Double-click the object to see the Code Window
• Event Procedure labeled
• ObjectName_EventName (e.g., cmdEnd_Click)
• Insert the event procedure that responds to an
  event between the Private Sub and End statements
• Able to switch among event procedures

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Object Name Prefixes - Examples

• Form frm
• Command button cmd
• Label lbl
• Text box txt
• List lst
• Radio button opt
• Others...

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Saving the Form and the Project

• Create a Folder for your project
• File, Save Project, or
• Click Save Project icon

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Concept of a VB Project

• Collection of files saved as .VBP file (a text
  file consisting of pointers and settings)
• Forms or form modules (.FRM files),
• Coded modules (.BAS files)
• Binary files - icons, pictures (.FRX files)
• Save forms and the project containing the forms

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File, Make .EXE Command

• Creates a standalone application
• Use the Icon property to specify image on
  minimized icon
• Run directly from Windows Explorer or as a
  Shortcut on your desktop
• May need a DLL to run
• c\windows\system\Msvbvm60.dll

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Printing Out Your Project

• File, Print
• Range Current Project
• Print What Form Image, Code
• Click OK

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Example Welcome to VB

• Add a command button
• Change its properties
• Caption Start
• Name cmdStart
• Add the following code
• Private Sub cmdStart_Click()
• ' The Start command button is used to display a
  message
• Dim message as String
• Print
• message"Welcome to VB"
• Print Spc(20) message 'Prints 20 spaces
  followed by the msg
• End Sub
• Save and run project

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Coded Statements and Methods

• Private - procedure will only work in the current
  form
• Remark (') - nonexecutable statements for
  documentation
• Dim - create variable and allocates memory
• Print - display on the screen
• Assignment () - assigns a value to a variable
• Cls - clears objects from the form (add this
  functionality!)

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Review of Controls

• Command button - activates a procedure
• Image Control - holds a picture has a stretch
  property to adjust the picture size
• Textboxes - for data entry
• Labels - displays text cannot be altered by the
  user

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Tab Order

• Order that VB highlights control when the user
  presses
• Tab or shift-Tab
• Arrow keys
• TabIndex Property in all controls
• Control with TabIndex 0 -- highlighted as soon
  as form opens
• As user hits tab key, the control with the
  TabIndex 1 is highlighted
• Default - TabIndex in order of the sequence the
  controls were created
• TabStop Property - remove a control from the tab
  order

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MessageBox

• Use to display brief messages such as errors,
  warning, or alerts in a dialog box
• returnvalue MsgBox(prompt, buttons, title)
• buttons value specifying the layout of the
  dialog box (may use VBs constants - pg. 127)
• returnvalue value indicating the command
  button clicked by the user

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Message Box Example

• Private Sub cmdError_Click()
• Dim Answer As String
• Answer MsgBox("Error found. Continue?",
  vbYesNoCancel, "Error")
• Print Answer
• End Sub