The DDX_FieldLBIndex function synchronizes the index of the selected item in a list box control in a record view and an int field data member of a recordset associated with the record view.
void AFXAPI DDX_FieldLBIndex( CDataExchange* pDX, int nIDC, int& index, CRecordset* pRecordset ); void AFXAPI DDX_FieldLBIndex( CDataExchange* pDX, int nIDC, int& index, CDaoRecordset* pRecordset );
A pointer to a CDataExchange object. The framework supplies this object to establish the context of the data exchange, including its direction.
A reference to a field data member in the associated CRecordset or CDaoRecordset object.
When moving data from the recordset to the control, this function sets the selection in the control based on the value specified in index. On a transfer from the recordset to the control, if the recordset field is Null, MFC sets the value of the index to 0. On a transfer from control to recordset, if the control is empty, the recordset field is set to 0.
Use the first version if you are working with the ODBC-based classes. Use the second version if you are working with the DAO-based classes.