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By default, a record view is associated with a single recordset object, whose fields are mapped to the record view's controls. Sometimes you might want to put a list box or combo box control in your record view and fill it with values from a second recordset object. The user can use the list box to select a new category of information to display in the record view. This topic explains how and when to do that.


Be aware that filling a combo box or list box from a data source might be slow. Take precautions against trying to fill a control from a recordset with a large number of records.

The model for this topic consists of a primary recordset that fills the controls of your form, while a secondary recordset fills a list box or combo box. Selecting a string from the list box causes your program to requery the primary recordset based on what was selected. The following procedure uses a combo box but applies equally to a list box.

To fill a combo box or list box from a second recordset

  1. Create the recordset object (CRecordset for ODBC, CDaoRecordset for DAO).

  2. Obtain a pointer to the CComboBox object for the combo box control.

  3. Empty the combo box of any previous contents.

  4. Move through all records in the recordset, calling CComboBox::AddString for each string from the current record you want to add to the combo box.

  5. Initialize the selection in the combo box.

В CopyCode imageCopy Code
void CSectionForm::OnInitialUpdate()
    // ...

    // Fill the combo box with all of the courses
    CENROLLDoc* pDoc = GetDocument();
    if (!pDoc->m_courseSet.Open())

    // ...

    if (pDoc->m_courseSet.IsOpen())
        while (!pDoc->m_courseSet.IsEOF() )

This function uses a second recordset, m_courseSet, which contains a record for each course offered, and a CComboBox control, m_ctlCourseList, which is stored in the record view class.

The function gets m_courseSet from the document and opens it. Then it empties m_ctlCourseList and scrolls through m_courseSet. For each record, the function calls the combo box's AddString member function to add the course ID value from the record. Finally, the code sets the combo box's selection.

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