The Initial BullsEye Source Files

The Initial CBullsEye Class Declaration

Listing 11.5 shows the initial wizard-generated class declaration for the CBullsEye control class. We have to make a number of changes to the class before it meets all the requirements described at the beginning of the chapter. For example, we need to add a few more base classes to obtain all the required control functionality. Also, presently the control supports no properties except the stock properties I selected via the wizard dialog boxes. Plus, there is quite of bit of implementation code to write to make the control draw and behave as a bull's eye. I'll get to all that, but first let's look at the initial source code.

I've reformatted the source code slightly from the original wizard-generated source code to group related functionality and to add a few comments (see Listing 11.5).

Listing 11.5. The Initial Wizard-Generated `CBullsEye` Class

// CBullsEye
class ATL_NO_VTABLE CBullsEye :
    // COM object support
    public CComObjectRootEx<CComSingleThreadModel>,
    // Class object support
    public CComCoClass<CBullsEye, &CLSID_BullsEye>,
    // Default dual interface for control.
    // Requests for properties preprocessed by
    // stock property base class
    public CStockPropImpl<CBullsEye, IBullsEye>,
    // Error info support for default dual interface
    public ISupportErrorInfo,
    // Basic "lite" control implementation
    public CComControl<CBullsEye>
    public IOleControlImpl<CBullsEye>,
    public IOleObjectImpl<CBullsEye>,
    public IOleInPlaceActiveObjectImpl<CBullsEye>,
    public IOleInPlaceObjectWindowlessImpl<CBullsEye>,
    public IViewObjectExImpl<CBullsEye>,
    // "Lite" control persistence implementation
    public IPersistStreamInitImpl<CBullsEye>,
    // Full control additional implementation
#ifndef _WIN32_WCE
    // Support for OLE Embedding
    public IDataObjectImpl<CBullsEye>,
#endif
    public IPersistStorageImpl<CBullsEye>,
    // Support for property pages
    public ISpecifyPropertyPagesImpl<CBullsEye>,
    // Support for fast activation
    public IQuickActivateImpl<CBullsEye>,
    // Connection point implementation
    public IConnectionPointContainerImpl<CBullsEye>,
    public CProxy_IBullsEyeEvents<CBullsEye>,
    public IProvideClassInfo2Impl<&CLSID_BullsEye,
        &__uuidof(_IBullsEyeEvents), &LIBID_BullsEyeControlLib>,
    // Selection of IPropertyNotifySink adds additional
    // connection point for property change notifications
    public IPropertyNotifySinkCP<CBullsEye>,
#ifdef _WIN32_WCE
    // IObjectSafety is required on Windows CE for the
    // control to be loaded correctly
    public IObjectSafetyImpl<CBullsEye,
        INTERFACESAFE_FOR_UNTRUSTED_CALLER>,
#endif
{
public:
    CBullsEye() { }

DECLARE_REGISTRY_RESOURCEID(IDR_BULLSEYE)
DECLARE_PROTECT_FINAL_CONSTRUCT()

    HRESULT FinalConstruct() { return S_OK; }

    void FinalRelease() { }

DECLARE_OLEMISC_STATUS(OLEMISC_RECOMPOSEONRESIZE |
    OLEMISC_CANTLINKINSIDE |
    OLEMISC_INSIDEOUT |
    OLEMISC_ACTIVATEWHENVISIBLE |
    OLEMISC_SETCLIENTSITEFIRST
)

BEGIN_COM_MAP(CBullsEye)
    // Default dual interface to control
    COM_INTERFACE_ENTRY(IBullsEye)
    COM_INTERFACE_ENTRY(IDispatch)
    // Error info support for default dual interface
    COM_INTERFACE_ENTRY(ISupportErrorInfo)
    // Basic "lite" control implementation
    COM_INTERFACE_ENTRY(IOleControl)
    COM_INTERFACE_ENTRY(IOleObject)
    COM_INTERFACE_ENTRY(IOleInPlaceActiveObject)
    COM_INTERFACE_ENTRY(IOleInPlaceObject)
    COM_INTERFACE_ENTRY(IOleInPlaceObjectWindowless)
    COM_INTERFACE_ENTRY2(IOleWindow, IOleInPlaceObjectWindowless)
    COM_INTERFACE_ENTRY(IViewObjectEx)
    COM_INTERFACE_ENTRY(IViewObject2)
    COM_INTERFACE_ENTRY(IViewObject)
    // "Lite" control persistence implementation
    COM_INTERFACE_ENTRY(IPersistStreamInit)
    COM_INTERFACE_ENTRY2(IPersist, IPersistStreamInit)
    // Full control additional implementation
    // Support for OLE Embedding
#ifndef _WIN32_WCE
    COM_INTERFACE_ENTRY(IDataObject)
#endif
    COM_INTERFACE_ENTRY(IPersistStorage)
    // Support for property pages
    COM_INTERFACE_ENTRY(ISpecifyPropertyPages)
    // Support for fast activation
    COM_INTERFACE_ENTRY(IQuickActivate)
    // Support for connection points
    COM_INTERFACE_ENTRY(IConnectionPointContainer)
    COM_INTERFACE_ENTRY(IProvideClassInfo)
    COM_INTERFACE_ENTRY(IProvideClassInfo2)
#ifdef _WIN32_WCE
    // IObjectSafety is required on Windows CE for the
    // control to be loaded correctly
    COM_INTERFACE_ENTRY_IID(IID_IObjectSafety, IObjectSafety)
#endif
END_COM_MAP()

// Initially, the control's stock properties are the only
// properties supported via persistence and property pages.
BEGIN_PROP_MAP(CBullsEye)
    PROP_DATA_ENTRY("_cx", m_sizeExtent.cx, VT_UI4)
    PROP_DATA_ENTRY("_cy", m_sizeExtent.cy, VT_UI4)
#ifndef _WIN32_WCE
    PROP_ENTRY("BackColor", DISPID_BACKCOLOR,
        CLSID_StockColorPage)
#endif
    PROP_ENTRY("BackStyle", DISPID_BACKSTYLE, CLSID_NULL)
    PROP_ENTRY("Enabled", DISPID_ENABLED, CLSID_NULL)
#ifndef _WIN32_WCE
    PROP_ENTRY("ForeColor", DISPID_FORECOLOR,
        CLSID_StockColorPage)
#endif
END_PROP_MAP()

BEGIN_CONNECTION_POINT_MAP(CBullsEye)
    // Property change notifications
    CONNECTION_POINT_ENTRY(IID_IPropertyNotifySink)
    // Our default connection point
    CONNECTION_POINT_ENTRY(__uuidof(_IBullsEyeEvents))
END_CONNECTION_POINT_MAP()

// Initially the control passes all Windows messages
// to the base class
BEGIN_MSG_MAP(CBullsEye)
    CHAIN_MSG_MAP(CComControl<CBullsEye>)
    DEFAULT_REFLECTION_HANDLER()
END_MSG_MAP()

// ISupportsErrorInfo
    STDMETHOD(InterfaceSupportsErrorInfo)(REFIID riid) {
        // Implementation deleted for clarity...
    }
    // IViewObjectEx
    DECLARE_VIEW_STATUS(VIEWSTATUS_SOLIDBKGND |
        VIEWSTATUS_OPAQUE)

// IBullsEye
public:
    HRESULT OnDraw(ATL_DRAWINFO& di) {
        // Sample drawing code omitted for clarity
    }

    // Storage for values of stock properties
    OLE_COLOR m_clrBackColor;
    LONG m_nBackStyle;
    BOOL m_bEnabled;
    OLE_COLOR m_clrForeColor;

    // Stock property change notification functions
    void OnBackColorChanged() {
        ATLTRACE(_T("OnBackColorChanged\n"));
    }
    void OnBackStyleChanged() {
        ATLTRACE(_T("OnBackStyleChanged\n"));
    }
    void OnEnabledChanged() {
        ATLTRACE(_T("OnEnabledChanged\n"));
    }
    void OnForeColorChanged() {
        ATLTRACE(_T("OnForeColorChanged\n"));
    }
};

The Initial IBullsEye Interface

Listing 11.6 is the initial wizard-generated IDL description for the IBullsEye interface. The wizard generates the interface containing any stock properties you've specified. We need to add all the custom properties for the control, as well as any stock and custom methods that the control supports.

Listing 11.6. The Initial Wizard-Generated IDL for the `IBullsEye` Interface

[
    object,
    uuid(B4FBD008-B03D-4F48-9C5B-4A981EB6A515),
    dual,
    nonextensible,
    helpstring("IBullsEye Interface"),
    pointer_default(unique)
]
interface IBullsEye : IDispatch{
    [propput, bindable, requestedit, id(DISPID_BACKCOLOR)]
    HRESULT BackColor([in]OLE_COLOR clr);
    [propget, bindable, requestedit, id(DISPID_BACKCOLOR)]
    HRESULT BackColor([out,retval]OLE_COLOR* pclr);
    [propput, bindable, requestedit, id(DISPID_BACKSTYLE)]
    HRESULT BackStyle([in]long style);
    [propget, bindable, requestedit, id(DISPID_BACKSTYLE)]
    HRESULT BackStyle([out,retval]long* pstyle);
    [propput, bindable, requestedit, id(DISPID_FORECOLOR)]
    HRESULT ForeColor([in]OLE_COLOR clr);
    [propget, bindable, requestedit, id(DISPID_FORECOLOR)]
    HRESULT ForeColor([out,retval]OLE_COLOR* pclr);
    [propput, bindable, requestedit, id(DISPID_ENABLED)]
    HRESULT Enabled([in]VARIANT_BOOL vbool);
    [propget, bindable, requestedit, id(DISPID_ENABLED)]
    HRESULT Enabled([out,retval]VARIANT_BOOL* pbool);
};

The Initial _IBullsEyeEvents Dispatch Interface

The initial _IBullsEyeEvents dispatch interface is empty (see Listing 11.7). We need to add the BullsEye custom events to the dispinterface. When a control supports any of the stock events, you add them to the event interface as well.

Listing 11.7. The Initial Wizard-Generated IDL for the `_IBullsEyeEvent` Dispatch Interface

[  uuid(58D6D8CB-765D-4C59-A41F-BBA8C40F7A14),
   helpstring("_IBullsEyeEvents Interface")
]
dispinterface _IBullsEyeEvents {
   properties:
   methods:
};