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ActiveX Controls in VB6

ActiveX Controls in VB6. What are ActiveX Controls?. Custom UI Controls Which you can design and add to the toolbox And then use in applications. Creating Simple ActiveX Controls. Start with New Project.. ActiveX Control Design/program as if a form Add a project to Group – test it in that

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ActiveX Controls in VB6

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  1. ActiveX Controls in VB6

  2. What are ActiveX Controls? • Custom UI Controls • Which you can design and add to the toolbox • And then use in applications

  3. Creating Simple ActiveX Controls • 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..

  4. The Clock Control 1

  5. Clock Control 2 • It will work by having a Timer • Which ticks every second • And gets system time • And displays it in a label

  6. Clock Control 3

  7. Clcok Control 4 - Testing

  8. Clock Control 5 – Normal exe project added

  9. Clock Control 6 – Set Test as Startup Or when you Run it it will start in a browser

  10. Clock Control 7 – The control in use

  11. Clock control 7 – Give it a name

  12. Clock Control 8 – Make .ocx file

  13. Clock Control 8 – Adding Control in a new project

  14. ActiveX Exercise 1 • Make a Clock control like this but.. • Have 3 fields showing hour, minute and second • Use hour() minute() and second() functions

  15. Controls with properties • 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

  16. ActiveX Controls are like Classes (as are forms) • They have methods • They have private data members • They have property let and get routines • Can set up events

  17. 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

  18. Properties modified at design-time • 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

  19. Example – a spinner control • Input integer values • Buttons to increase/decrease value • Need a StepSize property

  20. 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

  21. Dim ssize As Integer 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 Designer-user code

  22. Designer use

  23. .FRM contents 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 ..

  24. 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

  25. Adding Events to controls • 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..

  26. Control with Event .. Public Event Badkey() .. 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

  27. Designer writes event-handler

  28. 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

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