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DFX_Double

 

Transfers double float data between the field data members of a CDaoRecordset object and the columns of a record on the data source.

Syntax

      void AFXAPI DFX_Double(
   CDaoFieldExchange* pFX,
   LPCTSTR szName,
   double& value,
   DWORD dwBindOptions = AFX_DAO_ENABLE_FIELD_CACHE 
);

Parameters

  • pFX
    A pointer to an object of class CDaoFieldExchange. This object contains information to define the context for each call of the function.

  • szName
    The name of a data column.

  • value
    The value stored in the indicated data member — the value to be transferred. For a transfer from recordset to data source, the value, of type double, is taken from the specified data member. For a transfer from data source to recordset, the value is stored in the specified data member.

  • dwBindOptions
    An option that lets you take advantage of MFC's double buffering mechanism for detecting recordset fields that have changed. The default, AFX_DAO_ENABLE_FIELD_CACHE, uses double buffering. The other possible value is AFX_DAO_DISABLE_FIELD_CACHE. If you specify this value, MFC does no checking on this field. You must call SetFieldDirty and SetFieldNull yourself.

    Hinweis

    You can control whether data is double buffered by default by setting CDaoRecordset::m_bCheckCacheForDirtyFields.

Remarks

Data is mapped between type DAO_R8 in DAO and type double float in the recordset.

Example

See DFX_Text.

Requirements

Header: afxdao.h

See Also

MFC Macros and Globals
DFX_Text
DFX_Bool
DFX_Currency
DFX_Long
DFX_Short
DFX_Single
DFX_DateTime
DFX_Byte
DFX_Binary
DFX_LongBinary
CDaoFieldExchange::SetFieldType