ActiveX Controls in VB6

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ActiveX Controls in VB6
Sep-05 Slide:1
ActiveX Controls in VB
What are ActiveX Controls?
• Custom UI Controls
• Which you can design and add to the toolbox
• And then use in applications
Sep-05 Slide:2
ActiveX Controls in VB
Creating Simple ActiveX Controls
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Start with New Project.. ActiveX Control
Design/program as if a form
Add a project to Group – test it in that
Finally, produce a compiled OCX file
For example, a simple clock control..
Sep-05 Slide:3
ActiveX Controls in VB
The Clock Control 1
Sep-05 Slide:4
ActiveX Controls in VB
Clock Control 2
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It will work by having a Timer
Which ticks every second
And gets system time
And displays it in a label
Sep-05 Slide:5
ActiveX Controls in VB
Clock Control 3
Sep-05 Slide:6
ActiveX Controls in VB
Clcok Control 4 - Testing
Sep-05 Slide:7
ActiveX Controls in VB
Clock Control 5 – Normal exe project added
Sep-05 Slide:8
ActiveX Controls in VB
Clock Control 6 – Set Test as Startup
Or when you Run it it will
start in a browser
Sep-05 Slide:9
ActiveX Controls in VB
Clock Control 7 – The control in use
Sep-05 Slide:10
ActiveX Controls in VB
Clock control 7 – Give it a name
Sep-05 Slide:11
ActiveX Controls in VB
Clock Control 8 – Make .ocx file
Sep-05 Slide:12
ActiveX Controls in VB
Clock Control 8 – Adding Control in a new project
Sep-05 Slide:13
ActiveX Controls in VB
ActiveX Exercise 1
• Make a Clock control like this but..
• Have 3 fields showing hour, minute and second
• Use hour() minute() and second() functions
Sep-05 Slide:14
ActiveX Controls in VB
Controls with properties
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Most controls have properties used for design
Example background colour of textbox
And properties for user input
Such as text in a text box
ActiveX usually need the same
Sep-05 Slide:15
ActiveX Controls in VB
ActiveX Controls are like Classes (as are forms)
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They have
They have
They have
Can set up
Sep-05 Slide:16
ActiveX Controls in VB
methods
private data members
property let and get routines
events
Two 'users' of custom controls
• One user is the programmer who uses the control in
a form design
• The other is the final end-user who uses that form
• You have to write code for both types of user
Sep-05 Slide:17
ActiveX Controls in VB
Properties modified at design-time
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Need public property Let and Get
and private data member for internal representation
But
property values differ between control instances
and must 'persist' when Form not in memory
so must be written to disc somehow
actually stored in the .frm file
this persistence is not automated
Sep-05 Slide:18
ActiveX Controls in VB
Example – a spinner control
• Input integer values
• Buttons to increase/decrease value
• Need a StepSize property
Sep-05 Slide:19
ActiveX Controls in VB
End-user code
Private Sub Command1_Click()
Text1.Text = CInt(Text1.Text) + StepSize
End Sub
Private Sub Command2_Click()
Text1.Text = CInt(Text1.Text) - StepSize
End Sub
Sep-05 Slide:20
ActiveX Controls in VB
Dim ssize As Integer
Designer-user code
Public Property Let StepSize(val As Integer)
ssize = val
PropertyChanged "StepSize"
End Property
Public Property Get StepSize() As Integer
StepSize = ssize
End Property
Private Sub UserControl_WriteProperties(PropBag As PropertyBag)
PropBag.WriteProperty "StepSize", StepSize, 0
End Sub
Private Sub UserControl_ReadProperties(PropBag As PropertyBag)
StepSize = PropBag.ReadProperty("StepSize", 0)
End Sub
Private Sub UserControl_Initialize()
Text1.Text = 0
End Sub
Sep-05 Slide:21
ActiveX Controls in VB
Designer use
Sep-05 Slide:22
ActiveX Controls in VB
.FRM contents
Sep-05 Slide:23
ActiveX Controls in VB
VERSION 5.00
Object = "*\AspinnerProject.vbp"
Begin VB.Form Form1
..
ScaleWidth
= 4680
StartUpPosition = 3 'Windows Default
Begin Project1.UserControl1 UserControl12
Height
= 855
Left
= 840
..
_ExtentY
= 1508
StepSize
= 9
End
Begin Project1.UserControl1 UserControl11
Height
= 855
..
_ExtentY
= 873
StepSize
= 5
End
End
..
ActiveX Exercise 2
• Write a 'slider' control for numeric input
• When user drags mouse from area, input
is mouse Y
• Have textbox and pictureBox
• Program the mouseMove event of the
PictureBox, use the Y parameter
• Once working.. add a scale property set
at design-time
• Then expose a 'Value' property which
allows access to the number in the (Let
and Get) and read/write
Sep-05 Slide:24
ActiveX Controls in VB
Adding Events to controls
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A control can make an event occur
This would be a 'custom' event for the control
Designer can then program an event-handler for it
For example, in the spinner control, could hav ea
BadKey event if non-digit key pressed..
Sep-05 Slide:25
ActiveX Controls in VB
Control with Event
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Public Event Badkey()
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Private Sub Text1_KeyDown(KeyCode As Integer, Shift As Integer)
If KeyCode = 13 Or KeyCode = 8 Then Exit Sub 'Enter or backspace
If KeyCode < 48 Or KeyCode > 57 Then ' not 0 to 9
RaiseEvent Badkey
End If
End Sub
Sep-05 Slide:26
ActiveX Controls in VB
Designer writes event-handler
Sep-05 Slide:27
ActiveX Controls in VB
ActiveX Control Exercise 3
• Add a 2Click event to the slider control
• Triggered when picturebox double-clicked
• As designer, use it to zero the value
Sep-05 Slide:28
ActiveX Controls in VB
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