com connection points

COM Connection Points

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Content

The Client-Object-Sink Relationship IConnectionPointContainer &IConnectionPoint

Implementation using ATL/COM

COM Connection Points

The Client-Object-Sink Relationship

The Process of Connecting Source & Sink

ConnectableObject

ConnectableObject

ClientClient

Sink

Client passes sink interface pointer to connectable object.

Connectable object calls sink when appropriate.

One-to-Many Relationship

ConnectableObject

ConnectableObject

ClientClient

Sink

ClientClient

Sink

Sink

ClientClient

Sink

Many-to-One Relationship

ConnectableObject

ConnectableObject

ClientClient

SinkConnectable

Object

ConnectableObject

ConnectableObject

ConnectableObject

COM Connection Points

IConnectionPointContainer

&

IConnectionPoint

Connection Point ContainerConnection Point Container

IConnectionPointContainer &IConnectionPoint

Connection Point 1

Connection Point 2

Connection Point n

IConnectionPointContainer

IConnectionPoint

IConnectionPoint

IConnectionPoint

. .

.

IConnectionPointContainer

interface IConnectionPointContainer : IUnknown

{

HRESULT EnumConnectionPoints(

IEnumConnectionPoints **ppEnum) = 0;

HRESULT FindConnectionPoint(REFIID riid,

IConnectionPoint **ppCP) = 0;

};

interface IConnectionPointContainer : IUnknown

{

HRESULT EnumConnectionPoints(

IEnumConnectionPoints **ppEnum) = 0;

HRESULT FindConnectionPoint(REFIID riid,

IConnectionPoint **ppCP) = 0;

};

IConnectionPoint

interface IConnectionPoint : IUnknown

{

HRESULT GetConnectionInterface(IID *pIID) = 0;

HRESULT GetConnectionPointContainer(

IConnectionPointContainer **ppCPC) = 0;

HRESULT Advise(IUnknown *pUnk, DWORD *pdwCookie) = 0;

HRESULT Unadvise(DWORD dwCookie) = 0;

HRESULT EnumConnections(IEnumConnections **ppEnum) = 0;

};

interface IConnectionPoint : IUnknown

{

HRESULT GetConnectionInterface(IID *pIID) = 0;

HRESULT GetConnectionPointContainer(

IConnectionPointContainer **ppCPC) = 0;

HRESULT Advise(IUnknown *pUnk, DWORD *pdwCookie) = 0;

HRESULT Unadvise(DWORD dwCookie) = 0;

HRESULT EnumConnections(IEnumConnections **ppEnum) = 0;

};

COM Connection Points

Implementation using

ATL/COM

Step1. Create ATL/COM Project

Step1. Create ATL/COM Project

Step2. Create ATL Object

Step2. Create ATL Object

Step2. Create ATL Object

Step2. Create ATL Object

Step2. Create ATL Object

Step2. Create ATL Object

Step2. Create ATL Object

Step3. Modification of IDL// Timer.idl : IDL source for Timer.dll. . . . . . . . . . . . . . . . . . . . library TIMERLib{

importlib("stdole32.tlb");importlib("stdole2.tlb");[

uuid(A1EE119D-1107-4BB9-B23A-2D338F7F955F),helpstring("_IPeriodicTimerEvents Interface")

]dispinterface _IPeriodicTimerEvents{

properties:methods:

};

[uuid(FB1C62DE-5499-4C69-BC79-3EC6D5260D05),helpstring("PeriodicTimer Class")

]coclass PeriodicTimer{

[default] interface IPeriodicTimer;[default, source] dispinterface _IPeriodicTimerEvents;

};};

// Timer.idl : IDL source for Timer.dll. . . . . . . . . . . . . . . . . . . . library TIMERLib{

importlib("stdole32.tlb");importlib("stdole2.tlb");[

uuid(A1EE119D-1107-4BB9-B23A-2D338F7F955F),helpstring("_IPeriodicTimerEvents Interface")

]dispinterface _IPeriodicTimerEvents{

properties:methods:

};

[uuid(FB1C62DE-5499-4C69-BC79-3EC6D5260D05),helpstring("PeriodicTimer Class")

]coclass PeriodicTimer{

[default] interface IPeriodicTimer;[default, source] dispinterface _IPeriodicTimerEvents;

};};

Step3. Modification of IDL

// Timer.idl : IDL source for Timer.dll. . . . . . . . . . . . . . . . . . . . library TIMERLib{

importlib("stdole32.tlb");importlib("stdole2.tlb");[

uuid(A1EE119D-1107-4BB9-B23A-2D338F7F955F),helpstring("_IPeriodicTimerEvents Interface")

]interface _IPeriodicTimerEvents : IUnknown{};

[uuid(FB1C62DE-5499-4C69-BC79-3EC6D5260D05),helpstring("PeriodicTimer Class")

]coclass PeriodicTimer{

[default] interface IPeriodicTimer;[default, source] interface _IPeriodicTimerEvents;

};};

// Timer.idl : IDL source for Timer.dll. . . . . . . . . . . . . . . . . . . . library TIMERLib{

importlib("stdole32.tlb");importlib("stdole2.tlb");[

uuid(A1EE119D-1107-4BB9-B23A-2D338F7F955F),helpstring("_IPeriodicTimerEvents Interface")

]interface _IPeriodicTimerEvents : IUnknown{};

[uuid(FB1C62DE-5499-4C69-BC79-3EC6D5260D05),helpstring("PeriodicTimer Class")

]coclass PeriodicTimer{

[default] interface IPeriodicTimer;[default, source] interface _IPeriodicTimerEvents;

};};

Step4. Add Properties and Methods

Step4. Add Properties and Methods

Step4. Add Properties and Methods

Step4. Add Properties and Methods

Step4. Add Properties and Methods

Step4. Add Properties and Methods

Step4. Add Properties and Methods

Step4. Add Properties and Methods

Step4. Add Properties and Methods

Step4. Add Properties and Methods

Step4. Add Properties and Methods

Step4. Add Properties and Methods

Step5. Build Type Library

Step5. Build Type Library

Step5. Build Type Library

Step6. Implement Connection Point

Step6. Implement Connection Point

Step7. Detail the Source Code

See the Source Code for detail of other implementation.

Demonstration

Exercise

1. Implement an alarm clock object using ATL. In this COM object, you can set the alarm time, and the object will notify its sink when the time is up.