Step 1: Decide on Designer Architecture

Before you start using the framework, you have to make some fundamental decisions about the architecture of your designer. For instance:

• How is your designer going to be implemented?
  
  
• Will it have a separate run-time instance?
  
  
• Will it use the host's toolbox?
  
  
• Will it be a container?

You should know the answers to these questions before creating your designer class.

To start, use ATL to create a full ActiveX control that has the following interfaces:

Keep in mind the following requirements:

• A designer must have a window
  
  
• A designer cannot be considered an insertable control in Visual Basic
  
  
• A designer that supports ambient properties must include IViewObjectEx/IViewObjectExImpl.
  
  
• The design-time designer should support events.

Next, you can add an event interface to the object. . Specify an event interface in the IDL file and add it as the default event interface of the object. Then modify the IProvideDynamicClassInfoImpl event template parameter to include the IID of the event interface.

At this point you have a control, not a designer. To add the registration, toolbox, and container features required in the designer, you have to derive from CComDesignerBase or one of its derived classes.

The example below shows a typical design-time object that implements no special features. Because the design-time object implements a separate run-time object, it inherits from the IProvideDynamicClassInfoImpl interface.

class ATL_NO_VTABLE CDiffDsgnCtl : 
   public CComObjectRootEx<CComSingleThreadModel>,
   public CComCoClass<CDiffDsgnCtl, &CLSID_DiffDsgnCtl>,
   public CComControl<CDiffDsgnCtl>,
   public IDispatchImpl<IDifferentDesigner, 
      &IID_IDifferentDesigner, &LIBID_DIFFDSGNLib>,
   public IProvideClassInfo2Impl<&CLSID_DiffDsgnCtl, 
      &DIID_DDifferentDesigner, &LIBID_DIFFDSGNLib>,
   public IPersistStreamInitImpl<CDiffDsgnCtl>,
   public IPersistStorageImpl<CDiffDsgnCtl>,
   public IQuickActivateImpl<CDiffDsgnCtl>,
   public IOleControlImpl<CDiffDsgnCtl>,
   public IOleObjectImpl<CDiffDsgnCtl>,
   public IOleInPlaceActiveObjectImpl<CDiffDsgnCtl>,
   public IViewObjectExImpl<CDiffDsgnCtl>,
   public IOleInPlaceObjectWindowlessImpl<CDiffDsgnCtl>,
   public IDataObjectImpl<CDiffDsgnCtl>,
   public IConnectionPointContainerImpl<CDiffDsgnCtl>,
   public IConnectionPointImpl<CDiffDsgnCtl, &DIID_DDifferentDesigner>,
   public IActiveDesignerImpl<CDiffDsgnCtl, 
      &CLSID_DifferentInstance, 
      ISUPPORT_IPERSISTSTREAMINIT | ISUPPORT_IPERSISTSTORAGE,
      RUNTIME_MISCSTATUS>,
   public IProvideDynamicClassInfoImpl<CDiffDsgnCtl, 
      &CLSID_DifferentInstance, &DIID_DifferentInstance,&LIBID_DIFFINSTLib>,
   public CComDesignerBase<CDiffDsgnCtl, RegEntryArray>
{   . . .
};

See Also

Step 2: Set up the Registration File