ActiveX Controls

1. ActiveX Controls Jim Fawcett CSE775 – Distributed Objects Spring 2007

2. What is an ActiveX Control?Com Component • A COM component • User Interface • Has thread affinity, must live in an STA • Derives from CComObjectRootEx<CComSingleThread-Model> • Creatable class • Derives from CComCoClass • Provides IClassFactory interface

3. What is an ActiveX Control?Properties, callbacks, change notifications • Has stock and custom properties and methods • Implements IDispatch interface • Stock and custom event callbacks • Supports connection points • dispinterface, IConnectionPointContainer, IConnectionPoint, IProvideClassInfo2 • Property change notifications • IPropertyNotifySink, connection points

4. What is an ActiveX Control?Control behavior • On-demand rendering of view • IViewObject, IViewObject2, IViewObjectEx • Standard control behavior • IOleControl • In-place activation • IOleObject, IOleInPlaceActiveObject

5. What is an ActiveX Control?Persistence and Drag-and-Drop • Persistence support for containers • IPersistStreamInit, IPersistPropertyBag, IPersistStorage • Drag and Drop support • IDataObject, IDropSource, IDropTarget

6. What is an ActiveX Control?Design-Time Support • Provide property pages • ISpecifyPropertyPages • Property browsing from container • IPerPropertyBrowsing • Arrange properties by category • ICategorizeProperties

7. Control Types • “Standard” ActiveX control • Composite Control • A container and a control • HTML Control • Uses same webBrowser control as IE

8. What is a Control Container? • Provides a window • Acts as parent for the child COM control • Provides means for user to communicate with control, e.g., button-click, mouse-move, … • Support a set of COM interfaces that control uses to communicate with container

9. What is a Control Container?Basic containment • Control creation • CAxHostWindow has the base classes • CComCoClass • CComObjectRootEx<CComSingleThreadModel> • CWindowImpl • IOleClientSite • IOleInPlaceSiteWindowless • IOleControlSite • IOleContainer • IObjectWintSiteImpl • IServiceProvider • IAdviseSink

10. Container Window • Since the container provides a window for the control, you can do all the usual window things with it by sending windows messages: • Resize and move • Show and hide • CAxWindow provides a QueryControl method to obtain the control’s interface • HRESULT QueryControl(REFIID iid, void** ppUnk);

11. Sinking a Control’s Events • Connection Pointer interfaces • dispinterface, not dual interface, so container can’t just derive from, and implement those source interfaces • IDispatchImpl<nID, T, pdiid> • Derive once of each control • UsesBEGIN_SINK_MAP, SINK_ENTRY, END_SINK_MAP • Call IConnectionPointContainer, IConnectionPoint, IAdvise to establish link • Uses HRESULT AtlAdviseSinkMap(T* pT, bool bAdvise);

12. Sinking Control’s Property Notifications • Control defines IPropertyNotify interface • Request permission to change a property • Notify of a property change • IPropertyNotify is a dual interface • Container just inherits and implements • No need for sink map and IDispatchImpl • Implement STDMETHODIMP OnRequestEdit(DISPID dispID){ return S_OK; }STDMETHODIMP OnChanged(DISPID dispID){ m.bDirty = true; return S_OK; }