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CDaoErrorInfo Structure

  • Bài viết

The CDaoErrorInfo structure contains information about an error object defined for data access objects (DAO).

Note

DAO is supported through Office 2013. DAO 3.6 is the final version, and it's considered obsolete.

Syntax

struct CDaoErrorInfo
{
    long m_lErrorCode;
    CString m_strSource;
    CString m_strDescription;
    CString m_strHelpFile;
    long m_lHelpContext;
};

Parameters

m_lErrorCode
A numeric DAO error code. See the topic "Trappable Data Access Errors" in DAO Help.

m_strSource
The name of the object or application that originally generated the error. The Source property specifies a string expression representing the object that originally generated the error; the expression is usually the object's class name. For details, see the topic "Source Property" in DAO Help.

m_strDescription
A descriptive string associated with an error. For details, see the topic "Description Property" in DAO Help.

m_strHelpFile
A fully qualified path to a Microsoft Windows Help file. For details, see the topic "HelpContext, HelpFile Properties" in DAO Help.

m_lHelpContext
A context ID for a topic in a Microsoft Windows Help file. For details, see the topic "HelpContext, HelpFile Properties" in DAO Help.

Remarks

MFC does not encapsulate DAO error objects in a class. Instead, the CDaoException class supplies an interface for accessing the Errors collection contained in the DAO DBEngine object, the object that also contains all workspaces. When an MFC DAO operation throws a CDaoException object that you catch, MFC fills a CDaoErrorInfo structure and stores it in the exception object's m_pErrorInfo member. (If you choose to call DAO directly, you must call the exception object's GetErrorInfo member function yourself to fill m_pErrorInfo.)

For more information about handling DAO errors, see the article Exceptions: Database Exceptions. For related information, see the topic "Error Object" in DAO Help.

Information retrieved by the CDaoException::GetErrorInfo member function is stored in a CDaoErrorInfo structure. Examine the m_pErrorInfo data member from a CDaoException object that you catch in an exception handler, or call GetErrorInfo from a CDaoException object that you create explicitly in order to check errors that might have occurred during a direct call to the DAO interfaces. CDaoErrorInfo also defines a Dump member function in debug builds. You can use Dump to dump the contents of a CDaoErrorInfo object.

Requirements

Header: afxdao.h

See also

Structures, Styles, Callbacks, and Message Maps
CDaoException Class