Creating ActiveX Controls in Visual Basic 6 (VB6)

( Contents )

This chapter discusses a very important part of Microsoft's strategy for VB development—the ability to create ActiveX controls. Since Version 5 of VB, the VB programmer is not limited to using standard VB controls provided by Microsoft or custom controls provided by Microsoft and third parties.

Now VB developers can create their own ActiveX controls, either as an integral part of a larger VB project or as a standalone reusable component in an .OCX file. The information in this chapter provides a basic acquaintance of VB6 ActiveX control programming.

Contents

1. ActiveX Controls as ActiveX Components
   Creating ActiveX Controls from Constituent Controls
   Creating User-Drawn ActiveX Controls

2. The Lifetime of an ActiveX Control
   Control Authors and Developers

3. Special Considerations for ActiveX Control Development

4. Steps to Creating an ActiveX Control that Expose Properties
   The UserControl Object
         Giving Your Control a Custom Bitmap
         Accessing Ready-Made Control Features with the UserControl's Extender Object
         Getting Information About Your Control's Environment with the Ambient Object and the AmbientChanged Event
         Comparison of the Ambient and Extender Objects
   Implementing User-Drawn Graphic Features
   Implementing Custom Methods
   Implementing Custom Events
   Implementing Custom Properties
         Defining Properties with Get/Let/Set Procedures or Public Variables
   Implementing Property Persistence
         Using the InitProperties Event to Set Default Starting Property Values
         The InitProperties Event Versus the Initialize Event
         Using the Property Bag to Store Property Values
         Using ReadProperties and WriteProperties Events and Corresponding Methods to Maintain Persistent Properties
         Storing Persistent Property Values with the WriteProperties Event and the WriteProperty Method
         Calling the PropertyChanged Method to Trigger WriteProperties
         Retrieving Persistent Property Values with the ReadProperties Event and the ReadProperty Method
   Implementing Constituent Controls
   Implementing Delegated Methods
   Implementing Delegated Events
   Implementing Delegated Properties

5. Creating Data-Aware ActiveX Controls
   Enabling the Data-Binding Capabilities of an ActiveX Control
   Creating an ActiveX Control that Is a Data Source

6. Create and Enable Property Pages for ActiveX Controls

   Creating the PropertyPage Object's Visual Interface
   Determining Which Controls Are Selected for Editing With the SelectedControls Collection
   Using the SelectionChanged Event to Detect When the Developer Begins to Edit Properties
   Flagging Property Changes With the Changed Property
   Saving Property Changes With the ApplyChanges Event
   Connecting a Custom Control to a Property Page
   Connecting a Single Complex Property to a Property Page
   Detecting Which Complex Property Is Being Edited With the EditProperty Event
   Connecting a Property to a Standard VB Property Page

7. Testing and Debugging Your ActiveX Control
   Testing Your ActiveX Control With Existing Container Applications
   Testing and Debugging Your ActiveX Control in a Test Project
   What to Look for When Testing Your ActiveX Control