Creating the User Interface

1
Chapter 1

• Creating the User Interface
• Lesson 2 Overview of User Interface Elements

2
Learning Objectives

• Discuss the two types of Visual Basic
  controls.
• Add controls to a form.
• Explain control arrays.
• Set control and form properties.
• Assign code to event properties.
• Explain control and form collections.

3
What is a Form

• It provides a framework that you can use
  throughout your application to give a consistent
  look and feel to your user interface.

4
What is a control?

• Controls are objects that you add to a form.
  Each has it own set of properties, methods, and
  events that provide a specific capability to your
  application.

5
ActiveX controls

• Standard controls (command button, text box)
• Custom controls you can add to your project.
  (Microsoft Windows Common Controls 6.0, Microsoft
  Masked Edit Control 6.0)
• Some of commonly used ActiveX control such as
  TreeView, ListView, ImageList, ToolBar,
  StatusBar)

6
Adding ActiveX Controls

• To add an ActiveX control to the Components
  dialog box
• To add an ActiveX control to the Toolbox

7
Control Arrays

• You reference individual elements in the control
  array by an index.
• Example menu control, option button groupings.

8
Coding a Control Array

• controlname(index).property expression
• Private Sub chkPreferences_Click(Index As
  Integer)
• If chkPreferences(Index).Value vbChecked
  Then
• Select Case Index
• Case 0
• MsgBox "You will be notified by
  mail"
• Case 1
• MsgBox "You will be notified by
  phone"
• Case 2
• MsgBox "You will not be notified"
• End Select
• End If
• End Sub

9
Creating Controls at Run Time

• Private Sub Form_Load()
• Dim ctlWName As Control
• Set ctlWName frmName.Controls.Add("VB.TextBox",
  _
• "txtControlName", frmName)
• With ctlWName
• .Visible True
• .Top 200
• .Left 200
• .Width 2000
• .Height 200
• .Font.Size 10
• End With
• End Sub

10

• To set a control property at design time
• To set a property for multiple controls at design
  time
• Setting properties at run time

11
What is an event

• An event is a signal to your application that
  some kind of system or user activity has taken
  place.
• An event procedure is simply a procedure that is
  executed in response to a particular event
  (Click).
• Visual Basic events are triggered, or fired, by
  the system or by user action.
• Timer event in a Timer control (system event)
• Click event (by user action)

12
Standard Form Events

• Initialise (Before the form is loaded or
  displayed)
• Load (Form1.show or Load Form1)
• Activate (when focus is changing within the same
  application)
• Deactivate
• QueryUnload (you need to know how the user is
  closing the form)
• Unload (include form-level validation code needed
  for closing the form )
• Terminate (are removed from memory)

13

• Private Sub Exit_Click()
• End
• End Sub
• Private Sub Form_Activate()
• MsgBox "Active stage ..."
• End Sub
• Private Sub Form_Initialize()
• MsgBox "Initialise stage ...."
• End Sub
• Private Sub Form_Load()
• MsgBox "Loading stage ..."
• txtData.Font.Bold True
• txtData.Text "Hello World"
• End Sub
• Private Sub Form_QueryUnload(Cancel As Integer,
  UnloadMode As Integer)
• If UnloadMe ltgt vbFormCode Then
• MsgBox "Use the Exit button to close the form"
• Cancel True
• End If

14
What is a collection?

• A collection is a group of related objects.
• Examples
• A project can have a collection of forms.
• A form can have a collection of controls.

15
Creating a Collection

• Private Sub cmdCollection_Click()
• Dim col As New Collection
• Dim var As Variant
• col.Add "First Value"
• col.Add "Second Value"
• col.Add "Third Value"
• For Each var In col
• Debug.Print var
• Next var
• End Sub

16
Practice Using the Collection Objects Add Method

• Private colDroppedControls As New Collection
• Private Sub cmdListCollection_Click()
• Dim vnt As Variant
• For Each vnt In colDroppedControls
• Debug.Print vnt
• Next vnt
• End Sub

17

• Private Sub List1_DragDrop(Source As VB.Control,
  _
• X As Single, Y As Single)
• Dim vnt As Variant
• For Each vnt In colDroppedControls
• If vnt Is Source Then
• Beep
• Exit Sub
• End If
• Next
• colDroppedControls.Add Source
• List1.AddItem SourceName
• End Sub