SAMPLE: DAOPROP.EXE Sets a Custom Property on an Access Database with MFC DAO
ID: Q237285
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The information in this article applies to:
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Microsoft Visual C++, 32-bit Editions, version 6.0
SUMMARY
DAOPROP.exe is a sample that demonstrates adding a custom property to an Access database by using the MFC DAO classes and the underlying DAO OLE interfaces. It is based on article Q178745 that demonstrates the same concept by using Visual Basic for Applications in Access 97.
The MFC DAO classes expose a subset of the DAO hierarchy directly. The MFC DAO classes do not, however, expose all of the functionality available to developers using Visual Basic, Visual Basic for Applications or the DAO SDK in Visual C++. It is possible to use the complete hierarchy indirectly by using the underlying DAO OLE interfaces that the MFC DAO classes wrap.
For a description of using the DAO OLE interfaces see MFC technical note #54 in the Microsoft Developer Network (MSDN).
MORE INFORMATION
The DAO interfaces are defined in the file DBDAOINT.h in your \VC98\Include directory. When using the DAO OLE interfaces, it is often necessary to use the VARIANT and BSTR data types. These can be conveniently manipulated by using the wrapper class COleVariant. To initialize a VARIANT object with a BSTR string, it is necessary to use the VT_BSTRT type specified to make sure that the string is created as an ANSI string in ANSI builds, and as a UNICODE string in UNICODE builds. For more information about strings and DAO refer to article Q140599.
For a demonstration of initializing a COleVariant object and extracting values from it see the DAOVIEW sample in the MSDN.
The project included in the self-extracting executable is an MFC single document project. Its functionality is contained in the three menu handlers OnPropertyCreate(), OnPropertyGet(), and OnPropertySet(). These functions call the functions CreateCustomProp(), GetCustomProp(), and SetCustomProp() respectively.
Several concepts are demonstrated by this sample:
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Creating a COleVariant of type VT_BSTRT in OnPropertyCreate() and OnPropertyGet().
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Using the V_BSTRT macro to extract a string from a COleVariant in OnPropertyGet().
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Using the DAO OLE interfaces in CreateCustomProp(), GetCustomProp(), and SetCustomProp().
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Using the DAO_CHECK() macro to test the success of a DAO call and throw an exception in case of failure.
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Using the TRY, CATCH_ALL, END_CATCH_ALL and THROW_LAST macros to correctly handle exceptions when using the DAO OLE interfaces.
To check the custom property in your Access database file, open the file in Access 97, go to File - Database Properties and select on the Custom tab.
The following file is available for download from the Microsoft
Software Library. Click the file name below to download the file:
DaoProp.exe
Release Date:
For more information about how to download files from the Microsoft Software
Library, please see the following article in the Microsoft Knowledge Base:
Q119591 How to Obtain Microsoft Support Files from Online Services
| FileName |
Size |
|---|
| DaoProperty.asp |
42.8KB |
| DaoProperty.clw |
1.54KB |
| DaoProperty.cpp |
3.34KB |
| DaoProperty.dsp |
4.42KB |
| DaoProperty.dsw |
545 bytes |
| DaoProperty.h |
1.23KB |
| DaoProperty.ncb |
57.0KB |
| DaoProperty.opt |
47.5KB |
| DaoProperty.rc |
9.74KB |
| DaoPropertyDoc.cpp |
9.25KB |
| DaoPropertyDoc.h |
1.68KB |
| DaoPropertyView.cpp |
1.67KB |
| DaoPropertyView.h |
1.61KB |
| db1.mdb |
58.0KB |
| MainFrm.cpp |
1.70KB |
| MainFrm.h |
1.37KB |
| resource.h |
739 bytes |
| StdAfx.cpp |
213 bytes |
| StdAfx.h |
1.19KB |
| DaoProperty.ico |
1.05KB |
| DaoProperty.rc2 |
403 bytes |
| DaoPropertyDoc.ico |
1.05KB |
REFERENCES
For additional information about using DAO functions, please click the article number(s) below
to view the article(s) in the Microsoft Knowledge Base:
Q178745 ACC: Using DAO to Set and Retrieve Custom Database Properties
Q140599 PRB: MFC DAO Functions Accepting COleVariant Strings May Fail
For more information, please see the DAOVIEW sample located on the MSDN Web Workshop:
DAOVIEW sample in the MSDN
Additional query words:
Keywords : kbfile kbsample kbDAO kbVC kbVC600 kbGrpVCDB kbDSupport
Version : winnt:6.0
Platform : winnt
Issue type : kbhowto