Acknowledgement

1
Acknowledgement

• This presentation was created by
• Dr. Kurkovsky
• of Columbus State University

2
Events Outline

• Code window
• Form events
• Events of different controls

3
Code Window

• To open it
• Double-click on the form or on any of the
  controls
• Or right click on the form or on any of the
  controls and select View Code
• Important
• Set the Name property of a control before writing
  code for it

Control name
Title bar displays project name and module name
Event
This is where you write code
4
Event Procedures

• Event procedure runs in the response to an event
  that happens to a form or control.

Declares an event procedure
Name of the control or Form (for the form)
Event name
Marks the end of the event procedure
Your code goes here
5
How to Use Events

• Events are used to run some code that will
  perform a process based on some user action.
• Examples
• Initializing a form or control
• Changing the properties of a control or a form
• Making the form close.

Private Sub cmdClose_Click() Unload MeEnd Sub
Private Sub cmdMoveDown_Click()
frmEventsDemo.Top frmEventsDemo.Top 20End
Sub Private Sub cmdMoveUp_Click()
frmEventsDemo.Top frmEventsDemo.Top 20End Sub
6
Common Events

• Click
• DblClick
• Change
• GotFocus
• LostFocus
• KeyPress
• KeyDown
• KeyUp
• MouseDown
• MouseUp
• MouseMove

7
Form Events 1

• Display a form frmFormName Show
• Form_Initialize()The first event that occurs
  after calling the Show method. Controls are not
  yet loaded into memory. Occurs only once.
• Form_Load()The second event that occurs after
  calling the Show method. Form and controls are
  already loaded into memory. Occurs only once.
  Typical use
• Initialize variables
• Load initial data into controls (e.g. lists)
• Private Sub Form_Load() cmdSave.Enabled
  FalseEnd Sub

8
Form Events 2

• Form_Resize()Occurs whenever the form is resized
  by the user or by the source code. Typical use
• Shrink or move controls on the form
• Prevent the form from being too large or too
  small
• Private Sub Form_Resize() If Me.Height gt 3000
  Then Me.Height 3000 End If If Me.Width
  gt 6000 Then Me.Width 6000 End IfEnd
  Sub

9
Form Events 3

• Form_Activate()Occurs when the form gets focus.
  Typical use
• Update the status bar of the application
• Reverse the action of Deactivate() event (e.g.
  enable buttons)
• Private Sub Form_Activate() cmdClose.Enabled
  TrueEnd Sub
• Form_Deactivate()Occurs when the form loses
  focus. Typical use
• Reverse the action of Activate() event (e.g.
  disable buttons)
• Private Sub Form_Deactivate()
  cmdClose.Enabled FalseEnd Sub

10
Form Events 4

• Form_QueryUnload()Occurs when the user tries to
  unload the form by clocking the Close
  buttonAlso, event QueryUnload() can be triggered
  by Unload Mestatement. Typical use
• Ask the user whether s/he wants to close the
  application, save the data, etc.
• Form_Unload()Occurs before the form is unloaded.
  Typical use
• Restore the variables to the state prior to
  loading the form.
• Form_Terminate()The last event to fire when a
  form is unloaded. Typical use
• Clean up any form variables initialized in
  Form_Initialize() event.

11
Text Box Events

• TextBox_Change()Occurs when the user changes the
  text inside the text box. Example
• Enabling the Save button.

12
Command Button Events

• CommandButton_Click()Occurs when the user clicks
  on the command button or presses the hotkey.
  Example
• Enabling the Save button,
• Unloading the form.

13
Option Button Events

• OptionButton_Click()Occurs when the user clicks
  on a single option button or presses the hotkey.
  Example
• Enabling the Save button.
• Private Sub optFemale_Click() cmdSave.Enabled
  TrueEnd Sub
• Private Sub optMale_Click() cmdSave.Enabled
  TrueEnd Sub

14
Check Box Events

• CheckBox_Click()Occurs when the user clicks on a
  check box or presses the hotkey. Example
• Enabling the Save button.
• Private Sub chk401k_Click() cmdSave.Enabled
  TrueEnd Sub
• Private Sub chkBonus_Click() cmdSave.Enabled
  TrueEnd Sub
• Private Sub chkHealth_Click() cmdSave.Enabled
  TrueEnd Sub

15
Picture and Image Control Events

• Picture_Click()Occurs when the user clicks on a
  picture control. Example
• Opening another window.
• Private Sub picMail_Click() frmMessage.Show
  vbModalEnd Sub
• vbModal optional parameter indicates a modal
  window (dialog box)

16
List Box Events

• ListBox_Click()Occurs when the user clicks on an
  item in the list box. Example
• Showing a message with the selected item.
• Private Sub lstHealth_Click() MsgBox
  "Selected item " _ lstHealth.List(lstHealth
  .ListIndex), _ vbOKOnly, "List Box
  ControlEnd Sub
• ListBox_ItemCheck()Occurs when the user clicks
  on the checkbox of an item in the list box when
  Style property is set to 1-Check BoxExample
• Showing a message with the checked item
• Private Sub lstHealth_ItemCheck(Item As _
  Integer) MsgBox "Checked item " _
  lstHealth.List(Item), _ vbOKOnly, "List
  Box ControlEnd Sub

17
Combo Box Events

• ComboBox_Change()Occurs if the Style property is
  set to 0-DropDown Combo or 1-Simple Combo when
  the user changes the content of the text box
  component.
• ComboBox_Click()Occurs when the user clicks on
  an item in the list component. Example
• Enabling the Save Button
• Private Sub cboState_Click() cmdSave.Enabled
  True End Sub
• ComboBox_DropDown()Occurs if the Style property
  is set to 0-DropDown Combo or 2-DropDown List
  when the user opens the drop-down component.

18
Menu Events

• Menu_Click()Occurs when the user clicks on a
  menu item. Example
• Closing a window.
• Private Sub mnuFExit_Click() Unload Me End
  Sub
• Example
• Displaying a form