HOWTO: Iterate Controls on a Form from a Property Page

• Professional and Enterprise Editions of Microsoft Visual Basic, for Windows, version 5.0
• Microsoft Visual J++, version 1.0

SUMMARY

Microsoft Visual Basic version 5.0 enables you to create custom property pages for user-defined ActiveX controls. These property pages can contain controls and fields that change the properties of the user-defined control.

The property pages can also be extended to change properties of other controls that may be contained within the form where the user-defined control is located.

The property page, by default, can only access public properties of the user-defined control for which it was written. However, by using the ParentControls collection and a Friend function, you can create a route through which you can expose the other controls contained within the parent form.

The use of the Friend function enables components within the ActiveX control to use this function, while hiding it from use outside the immediate project. The ParentControls collection returns the objects within the parent container. This includes returning item(0) as a reference to the parent container.

MORE INFORMATION

To enable a property page for a user-defined ActiveX control to gain access to the container form's set of controls, do the following:

1. Start Microsoft Visual Basic. Load an ActiveX control project, or create a new one.

2. Add the following code in the control's code window:

         Friend Function FormControls() As Object
             Set FormControls = ParentControls
             'Returns the collection of controls on the parent form.
         End Function
   
   

3. From the Project menu, click Add Property Page.

4. Add the following code in the Property Page's code window:

         Private Sub PropertyPage_SelectionChanged()
             Dim UC As UserControl1  'Make sure that UC is typed explicitly as
                                     'the user-defined control you are working
                                     'with. To use Friend functions, you must
                                     'early-bind your variables.
             Dim Ctrl As Object
             Set UC = SelectedControls(0)  'Return selected control.
             For Each Ctrl In UC.FormControls  'Iterate through the use of
                                               'UC's friend function.
             Debug.Print Ctrl.Name  'Output the name of each control.
             Next Ctrl
         End Sub
   
   

5. Switch to the UserControl1 object. On the properties list, click Property Pages. Turn on the option for PropertyPage1.

'Custom' from the properties list to bring up the Property Page.

REFERENCES

Microsoft Visual Basic Online Help Keywords: Friend, Extender