Dialog Data Exchange Functions for CRecordView and CDaoRecordView
The latest version of this topic can be found at Dialog Data Exchange Functions for CRecordView and CDaoRecordView.
This topic lists the DDX_Field functions used to exchange data between a CRecordset and a CRecordView form or a CDaoRecordset and a CDaoRecordView form.
Note
DDX_Field functions are like DDX functions in that they exchange data with controls in a form. But unlike DDX, they exchange data with the fields of the view's associated recordset object rather than with fields of the record view itself. For more information, see classes CRecordView and CDaoRecordView.
DDX_Field Functions
| DDX_FieldCBIndex | Transfers integer data between a recordset field data member and the index of the current selection in a combo box in a CRecordView or CDaoRecordView. |
| DDX_FieldCBString | Transfers CString data between a recordset field data member and the edit control of a combo box in a CRecordView or CDaoRecordView. When moving data from the recordset to the control, this function selects the item in the combo box that begins with the characters in the specified string. |
| DDX_FieldCBStringExact | Transfers CString data between a recordset field data member and the edit control of a combo box in a CRecordView or CDaoRecordView. When moving data from the recordset to the control, this function selects the item in the combo box that exactly matches the specified string. |
| DDX_FieldCheck | Transfers Boolean data between a recordset field data member and a check box in a CRecordView or CDaoRecordView. |
| DDX_FieldLBIndex | Transfers integer data between a recordset field data member and the index of the current selection in a list box in a CRecordView or CDaoRecordView. |
| DDX_FieldLBString | Manages the transfer of CString data between a list-box control and the field data members of a recordset. When moving data from the recordset to the control, this function selects the item in the list box that begins with the characters in the specified string. |
| DDX_FieldLBStringExact | Manages the transfer of CString data between a list-box control and the field data members of a recordset. When moving data from the recordset to the control, this function selects the first item that exactly matches the specified string. |
| DDX_FieldRadio | Transfers integer data between a recordset field data member and a group of radio buttons in a CRecordView or CDaoRecordView. |
| DDX_FieldScroll | Sets or gets the scroll position of a scroll bar control in a CRecordView or CDaoRecordView. Call from your DoFieldExchange function. |
| DDX_FieldText | Overloaded versions are available for transferring int, UINT, long, DWORD, CString, float, double, short, COleDateTime, and COleCurrency data between a recordset field data member and an edit box in a CRecordView or CDaoRecordView. |
DDX_FieldCBIndex
The DDX_FieldCBIndex function synchronizes the index of the selected item in the list box control of a combo box control in a record view and an int field data member of a recordset associated with the record view.
void AFXAPI DDX_FieldCBIndex(
CDataExchange* pDX,
int nIDC,
int& index,
CRecordset* pRecordset);
void AFXAPI DDX_FieldCBIndex(
CDataExchange* pDX,
int nIDC,
int& index,
CDaoRecordset* pRecordset);
Parameters
pDX
A pointer to a CDataExchange object. The framework supplies this object to establish the context of the data exchange, including its direction.
nIDC
The ID of a control in the CRecordView or CDaoRecordView object.
index
A reference to a field data member in the associated CRecordset or CDaoRecordset object.
pRecordset
A pointer to the CRecordset or CDaoRecordset object with which data is exchanged.
Remarks
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 or if no item is selected, 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.
For more information about DDX, see Dialog Data Exchange and Validation. For examples and more information about DDX for CRecordView and CDaoRecordView fields, see the article Record Views.
Example
See DDX_FieldText for a general DDX_Field example. The example would be similar for DDX_FieldCBIndex.
DDX_FieldCBString
The DDX_FieldCBString 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_FieldCBString(
CDataExchange* pDX,
int nIDC,
CString& value,
CRecordset* pRecordset);
void AFXAPI DDX_FieldCBString(
CDataExchange* pDX,
int nIDC,
CString& value,
CDaoRecordset* pRecordset);
Parameters
pDX
A pointer to a CDataExchange object. The framework supplies this object to establish the context of the data exchange, including its direction.
nIDC
The ID of a control in the CRecordView or CDaoRecordView object.
value
A reference to a field data member in the associated CRecordset or CDaoRecordset object.
pRecordset
A pointer to the CRecordset or CDaoRecordset object with which data is exchanged.
Remarks
When moving data from the recordset to the control, this function sets the current selection in the combo box to the first row that begins with the characters in 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 control 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 if the field permits.
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.
For more information about DDX, see Dialog Data Exchange and Validation. For examples and more information about DDX for CRecordView and CDaoRecordView fields, see the article Record Views.
Example
See DDX_FieldText for a general DDX_Field example. The example includes a call to DDX_FieldCBString.
DDX_FieldCBStringExact
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);
Parameters
pDX
A pointer to a CDataExchange object. The framework supplies this object to establish the context of the data exchange, including its direction.
nIDC
The ID of a control in the CRecordView or CDaoRecordView object.
value
A reference to a field data member in the associated CRecordset or CDaoRecordset object.
pRecordset
A pointer to the CRecordset or CDaoRecordset object with which data is exchanged.
Remarks
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.
For more information about DDX, see Dialog Data Exchange and Validation. For examples and more information about DDX for CRecordView and CDaoRecordView fields, see the article Record Views.
Example
See DDX_FieldText for a general DDX_Field example. Calls to DDX_FieldCBStringExact would be similar.
DDX_FieldCheck
The DDX_FieldCheck function manages the transfer of int data between a check box control in a dialog box, form view, or control view object and an int data member of the dialog box, form view, or control view object.
void AFXAPI DDX_FieldCheck(
CDataExchange* pDX,
int nIDC,
int& value,
CRecordset* pRecordset);
void AFXAPI DDX_FieldCheck(
CDataExchange* pDX,
int nIDC,
int& value,
CDaoRecordset* pRecordset);
Parameters
pDX
A pointer to a CDataExchange object. The framework supplies this object to establish the context of the data exchange, including its direction.
nIDC
The resource ID of the check box control associated with the control property.
value
A reference to a member variable of the dialog box, form view, or control view object with which data is exchanged.
pRecordset
A pointer to the CRecordset or CDaoRecordset object with which data is exchanged.
Remarks
When DDX_FieldCheck is called, value is set to the current state of the check box control, or the control's state is set to value, depending on the direction of transfer.
For more information about DDX, see Dialog Data Exchange and Validation.
DDX_FieldLBIndex
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);
Parameters
pDX
A pointer to a CDataExchange object. The framework supplies this object to establish the context of the data exchange, including its direction.
nIDC
The ID of a control in the CRecordView or CDaoRecordView object.
index
A reference to a field data member in the associated CRecordset or CDaoRecordset object.
pRecordset
A pointer to the CRecordset or CDaoRecordset object with which data is exchanged.
Remarks
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.
For more information about DDX, see Dialog Data Exchange and Validation. For examples and more information about DDX for CRecordView and CDaoRecordView fields, see the article Record Views.
Example
See DDX_FieldText for a general DDX_Field example.
DDX_FieldLBString
The DDX_FieldLBString copies the current selection of a list box control in a record view to a CString field data member of a recordset associated with the record view.
void AFXAPI DDX_FieldLBString(
CDataExchange* pDX,
int nIDC,
CString& value,
CRecordset* pRecordset);
void AFXAPI DDX_FieldLBString(
CDataExchange* pDX,
int nIDC,
CString& value,
CDaoRecordset* pRecordset);
Parameters
pDX
A pointer to a CDataExchange object. The framework supplies this object to establish the context of the data exchange, including its direction.
nIDC
The ID of a control in the CRecordView or CDaoRecordView object.
value
A reference to a field data member in the associated CRecordset or CDaoRecordset object.
pRecordset
A pointer to the CRecordset or CDaoRecordset object with which data is exchanged.
Remarks
In the reverse direction, this function sets the current selection in the list box to the first row that begins with the characters in the string specified by value. On a transfer from the recordset to the control, if the recordset field is Null, any selection is removed from the list box. 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.
For more information about DDX, see Dialog Data Exchange and Validation. For examples and more information about DDX for CRecordView and CDaoRecordView fields, see the article Record Views.
Example
See DDX_FieldText for a general DDX_Field example. Calls to DDX_FieldLBString would be similar.
DDX_FieldLBStringExact
The DDX_FieldLBStringExact function copies the current selection of a list box control in a record view to a CString field data member of a recordset associated with the record view.
void AFXAPI DDX_FieldLBStringExact(
CDataExchange* pDX,
int nIDC,
CString& value,
CRecordset* pRecordset);
void AFXAPI DDX_FieldLBStringExact(
CDataExchange* pDX,
int nIDC,
CString& value,
CDaoRecordset* pRecordset);
Parameters
pDX
A pointer to a CDataExchange object. The framework supplies this object to establish the context of the data exchange, including its direction.
nIDC
The ID of a control in the CRecordView or CDaoRecordView object.
value
A reference to a field data member in the associated CRecordset or CDaoRecordset object.
pRecordset
A pointer to the CRecordset or CDaoRecordset object with which data is exchanged.
Remarks
In the reverse direction, this function sets the current selection in the list 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 list box. 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.
For more information about DDX, see Dialog Data Exchange and Validation. For examples and more information about DDX for CRecordView and CDaoRecordView fields, see the article Record Views.
Example
See DDX_FieldText for a general DDX_Field example. Calls to DDX_FieldLBStringExact would be similar.
DDX_FieldRadio
The DDX_FieldRadio function associates a zero-based int member variable of a record view's recordset with the currently selected radio button in a group of radio buttons in the record view.
void AFXAPI DDX_FieldRadio(
CDataExchange* pDX,
int nIDC,
int& value,
CRecordset* pRecordset);
void AFXAPI DDX_FieldRadio(
CDataExchange* pDX,
int nIDC,
int& value,
CDaoRecordset* pRecordset);
Parameters
pDX
A pointer to a CDataExchange object. The framework supplies this object to establish the context of the data exchange, including its direction.
nIDC
The ID of the first in a group (with style WS_GROUP) of adjacent radio button controls in the CRecordView or CDaoRecordView object.
value
A reference to a field data member in the associated CRecordset or CDaoRecordset object.
pRecordset
A pointer to the CRecordset or CDaoRecordset object with which data is exchanged.
Remarks
When transferring from the recordset field to the view, this function turns on the nth radio button (zero-based) and turns off the other buttons. In the reverse direction, this function sets the recordset field to the ordinal number of the radio button that is currently on (checked). On a transfer from the recordset to the control, if the recordset field is Null, no button is selected. On a transfer from control to recordset, if no control is selected, the recordset field is set to Null if the field permits that.
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.
For more information about DDX, see Dialog Data Exchange and Validation. For examples and more information about DDX for CRecordView and CDaoRecordView fields, see the article Record Views.
Example
See DDX_FieldText for a general DDX_Field example. Calls to DDX_FieldRadio would be similar.
DDX_FieldScroll
The DDX_FieldScroll function synchronizes the scroll position of a scroll bar control in a record view and an int field data member of a recordset associated with the record view (or with whatever integer variable you choose to map it to).
void AFXAPI DDX_FieldScroll(
CDataExchange* pDX,
int nIDC,
int& value,
CRecordset* pRecordset);
void AFXAPI DDX_FieldScroll(
CDataExchange* pDX,
int nIDC,
int& value,
CDaoRecordset* pRecordset);
Parameters
pDX
A pointer to a CDataExchange object. The framework supplies this object to establish the context of the data exchange, including its direction.
nIDC*
The ID of the first in a group (with style WS_GROUP) of adjacent radio button controls in the CRecordView or CDaoRecordView object.
value
A reference to a field data member in the associated CRecordset or CDaoRecordset object.
pRecordset
A pointer to the CRecordset or CDaoRecordset object with which data is exchanged.
Remarks
When moving data from the recordset to the control, this function sets the scroll position of the scroll bar control to the value specified in value. On a transfer from the recordset to the control, if the recordset field is Null, the scroll bar control is set to 0. On a transfer from control to recordset, if the control is empty, the value of the recordset field is 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.
For more information about DDX, see Dialog Data Exchange and Validation. For examples and more information about DDX for CRecordView and CDaoRecordView fields, see the article Record Views.
Example
See DDX_FieldText for a general DDX_Field example. Calls to DDX_FieldScroll would be similar.
DDX_FieldText
The DDX_FieldText function manages the transfer of int, short, long, DWORD, CString, float, double, BOOL, or BYTE data between an edit box control and the field data members of a recordset.
void AFXAPI DDX_FieldText(
CDataExchange* pDX,
int nIDC,
BYTE& value,
CRecordset* pRecordset);
void AFXAPI DDX_FieldText(
CDataExchange* pDX,
int nIDC,
int& value,
CRecordset* pRecordset);
void AFXAPI DDX_FieldText(
CDataExchange* pDX,
int nIDC,
UINT& value,
CRecordset* pRecordset);
void AFXAPI DDX_FieldText(
CDataExchange* pDX,
int nIDC,
long& value,
CRecordset* pRecordset);
void AFXAPI DDX_FieldText(
CDataExchange* pDX,
int nIDC,
DWORD& value,
CRecordset* pRecordset);
void AFXAPI DDX_FieldText(
CDataExchange* pDX,
int nIDC,
CString& value,
CRecordset* pRecordset);
void AFXAPI DDX_FieldText(
CDataExchange* pDX,
int nIDC,
float& value,
CRecordset* pRecordset);
void AFXAPI DDX_FieldText(
CDataExchange* pDX,
int nIDC,
double& value,
CRecordset* pRecordset);
void AFXAPI DDX_FieldText(
CDataExchange* pDX,
int nIDC,
short& value,
CDaoRecordset* pRecordset);
void AFXAPI DDX_FieldText(
CDataExchange* pDX,
int nIDC,
BOOL& value,
CDaoRecordset* pRecordset);
void AFXAPI DDX_FieldText(
CDataExchange* pDX,
int nIDC,
BYTE& value,
CDaoRecordset* pRecordset);
void AFXAPI DDX_FieldText(
CDataExchange* pDX,
int nIDC,
long& value,
CDaoRecordset* pRecordset);
void AFXAPI DDX_FieldText(
CDataExchange* pDX,
int nIDC,
DWORD& value,
CDaoRecordset* pRecordset);
void AFXAPI DDX_FieldText(
CDataExchange* pDX,
int nIDC,
CString& value,
CDaoRecordset* pRecordset);
void AFXAPI DDX_FieldText(
CDataExchange* pDX,
int nIDC,
float& value,
CDaoRecordset* pRecordset);
void AFXAPI DDX_FieldText(
CDataExchange* pDX,
int nIDC,
double& value,
CDaoRecordset* pRecordset);
void AFXAPI DDX_FieldText(
CDataExchange* pDX,
int nIDC,
COleDateTime& value,
CDaoRecordset* pRecordset);
void AFXAPI DDX_FieldText(
CDataExchange* pDX,
int nIDC,
COleCurrency& value,
CDaoRecordset* pRecordset);
Parameters
pDX
A pointer to a CDataExchange object. The framework supplies this object to establish the context of the data exchange, including its direction.
nIDC
The ID of a control in the CRecordView or CDaoRecordView object.
value
A reference to a field data member in the associated CRecordset or CDaoRecordset object. The data type of value depends on which of the overloaded versions of DDX_FieldText you use.
pRecordset
A pointer to the CRecordset or CDaoRecordset object with which data is exchanged. This pointer enables DDX_FieldText to detect and set Null values.
Remarks
For CDaoRecordset objects, DDX_FieldText also manages transferring COleDateTime, and COleCurrency values. An empty edit box control indicates a Null value. On a transfer from the recordset to the control, if the recordset field is Null, the edit 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 versions with CRecordset parameters if you are working with the ODBC-based classes. Use the versions with CDaoRecordset parameters if you are working with the DAO-based classes.
For more information about DDX, see Dialog Data Exchange and Validation. For examples and more information about DDX for CRecordView and CDaoRecordView fields, see the article Record Views.
Example
The following DoDataExchange function for a CRecordView contains DDX_FieldText function calls for three data types: IDC_COURSELIST is a combo box; the other two controls are edit boxes. For DAO programming, the m_pSet parameter is a pointer to a CRecordset or CDaoRecordset.
void CMyDaoRecordView::DoDataExchange(CDataExchange* pDX)
{
CDaoRecordView::DoDataExchange(pDX);
DDX_FieldCBString(pDX, IDC_LASTNAME, m_pSet->m_LastName, m_pSet);
DDX_FieldText(pDX, IDC_ID, m_pSet->m_EmployeeID, m_pSet);
DDX_FieldText(pDX, IDC_AGE, m_pSet->m_Age, m_pSet);
}