Class Factories and Licensing
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The latest version of this topic can be found at Class Factories and Licensing.
To create an instance of your OLE control, a container application calls a member function of the control's class factory. Because your control is an actual OLE object, the class factory is responsible for creating instances of your control. Every OLE control class must have a class factory.
Another important feature of OLE controls is their ability to enforce a license. ControlWizard allows you to incorporate licensing during the creation of your control project. For more information on control licensing, see the article ActiveX Controls: Licensing An ActiveX Control.
The following table lists several macros and functions used to declare and implement your control's class factory and to license of your control.
Class Factories and Licensing
| DECLARE_OLECREATE_EX | Declares the class factory for an OLE control or property page. |
| IMPLEMENT_OLECREATE_EX | Implements the control's GetClassID function and declares an instance of the class factory. |
| BEGIN_OLEFACTORY | Begins the declaration of any licensing functions. |
| END_OLEFACTORY | Ends the declaration of any licensing functions. |
| AfxVerifyLicFile | Verifies whether a control is licensed for use on a particular computer. |
DECLARE_OLECREATE_EX
Declares a class factory and the GetClassID member function of your control class.
DECLARE_OLECREATE_EX
(class_name)
Parameters
class_name
The name of the control class.
Remarks
Use this macro in the control class header file for a control that does not support licensing.
Note that this macro serves the same purpose as the following code sample:
BEGIN_OLEFACTORY(CMyAxCtrl)
END_OLEFACTORY(CMyAxCtrl)
IMPLEMENT_OLECREATE_EX
Implements your control's class factory and the GetClassID member function of your control class.
IMPLEMENT_OLECREATE_EX(
class_name,
external_name,
l,
w1,
w2,
b1,
b2,
b3,
b4,
b5,
b6,
b7,
b8)
Parameters
class_name
The name of the control property page class.
external_name
The object name exposed to applications.
l, w1, w2, b1, b2, b3, b4, b5, b6, b7, b8
Components of the class's CLSID. For more information on these parameters, see the Remarks for [IMPLEMENT_OLECREATE]--brokenlink--(../Topic/not%20found.md#implement_olecreate.
Remarks
This macro must appear in the implementation file for any control class that uses the DECLARE_OLECREATE_EX macro or the BEGIN_OLEFACTORY and END_OLEFACTORY macros. The external name is the identifier of the OLE control that is exposed to other applications. Containers use this name to request an object of this control class.
BEGIN_OLEFACTORY
Begins the declaration of your class factory in the header file of your control class.
BEGIN_OLEFACTORY
(class_name)
Parameters
class_name
Specifies the name of the control class whose class factory this is.
Remarks
Declarations of class factory licensing functions should begin immediately after BEGIN_OLEFACTORY.
END_OLEFACTORY
Ends the declaration of your control's class factory.
END_OLEFACTORY
(class_name)
Parameters
class_name
The name of the control class whose class factory this is.
AfxVerifyLicFile
Call this function to verify that the license file named by pszLicFileName is valid for the OLE control.
BOOL AFXAPI AfxVerifyLicFile(
HINSTANCE hInstance,
LPCTSTR pszLicFileName,
LPOLESTR pszLicFileContents,
UINT cch = -1);
Parameters
hInstance
The instance handle of the DLL associated with the licensed control.
pszLicFileName
Points to a null-terminated character string containing the license filename.
pszLicFileContents
Points to a byte sequence that must match the sequence found at the beginning of the license file.
cch
Number of characters in pszLicFileContents.
Return Value
Nonzero if the license file exists and begins with the character sequence in pszLicFileContents; otherwise 0.
Remarks
If cch is – 1, this function uses:
_tcslen(pszLicFileContents);