CComContainedObject Class
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This class implements IUnknown by delegating to the owner object's IUnknown.
Important
This class and its members cannot be used in applications that execute in the Windows Runtime.
Syntax
template<class Base>
class CComContainedObject : public Base
Parameters
Base
Your class, derived from CComObjectRoot or CComObjectRootEx.
Members
Public Constructors
| Name | Description |
|---|---|
| CComContainedObject::CComContainedObject | The constructor. Initializes the member pointer to the owner object's IUnknown. |
| CComContainedObject::~CComContainedObject | The destructor. |
Public Methods
| Name | Description |
|---|---|
| CComContainedObject::AddRef | Increments the reference count on the owner object. |
| CComContainedObject::GetControllingUnknown | Retrieves the owner object's IUnknown. |
| CComContainedObject::QueryInterface | Retrieves a pointer to the interface requested on the owner object. |
| CComContainedObject::Release | Decrements the reference count on the owner object. |
Remarks
ATL uses CComContainedObject in classes CComAggObject, CComPolyObject, and CComCachedTearOffObject. CComContainedObject implements IUnknown by delegating to the owner object's IUnknown. (The owner is either the outer object of an aggregation, or the object for which a tear-off interface is being created.) CComContainedObject calls CComObjectRootEx's OuterQueryInterface, OuterAddRef, and OuterRelease, all inherited through Base.
Inheritance Hierarchy
Base
CComContainedObject
Requirements
Header: atlcom.h
CComContainedObject::AddRef
Increments the reference count on the owner object.
STDMETHOD_(ULONG, AddRef)();
Return Value
A value that may be useful for diagnostics or testing.
CComContainedObject::CComContainedObject
The constructor.
CComContainedObject(void* pv);
Parameters
pv
[in] The owner object's IUnknown.
Remarks
Sets the m_pOuterUnknown member pointer (inherited through the Base class) to pv.
CComContainedObject::~CComContainedObject
The destructor.
~CComContainedObject();
Remarks
Frees all allocated resources.
CComContainedObject::GetControllingUnknown
Returns the m_pOuterUnknown member pointer (inherited through the Base class) that holds the owner object's IUnknown.
IUnknown* GetControllingUnknown();
Return Value
The owner object's IUnknown.
Remarks
This method may be virtual if Base has declared the DECLARE_GET_CONTROLLING_UNKNOWN macro.
CComContainedObject::QueryInterface
Retrieves a pointer to the interface requested on the owner object.
STDMETHOD(QueryInterface)(REFIID iid, void** ppvObject);
template <class Q>
HRESULT STDMETHODCALLTYPE QueryInterface(Q** pp);
Parameters
iid
[in] The identifier of the interface being requested.
ppvObject
[out] A pointer to the interface pointer identified by iid. If the object does not support this interface, ppvObject is set to NULL.
pp
[out] A pointer to the interface pointer identified by type Q. If the object does not support this interface, pp is set to NULL.
Return Value
A standard HRESULT value.
CComContainedObject::Release
Decrements the reference count on the owner object.
STDMETHOD_(ULONG, Release)();
Return Value
In debug builds, Release returns a value that may be useful for diagnostics or testing. In non-debug builds, Release always returns 0.