The DDX_FieldCBStringExact function manages the transfer of CString data between the edit control of a combo box control in a record view and a CString field data member of a recordset associated with the record view.
void AFXAPI DDX_FieldCBStringExact( CDataExchange* pDX, int nIDC, CString& value, CRecordset* pRecordset ); void AFXAPI DDX_FieldCBStringExact( CDataExchange* pDX, int nIDC, CString& value, CDaoRecordset* pRecordset );
When moving data from the recordset to the control, this function sets the current selection in the combo box to the first row that exactly matches the string specified in value. On a transfer from the recordset to the control, if the recordset field is NULL, any selection is removed from the combo box and the edit box of the combo box is set to empty. On a transfer from control to recordset, if the control is empty, the recordset field is set to NULL.
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.
See DDX_FieldText for a general DDX_Field example. Calls to DDX_FieldCBStringExact would be similar.