addixdlg.cpp

一个作的很好的dao数据库开发

		// either there never was a field name specified or the user has
		// chosen not to add the field
		if (retCode == IDYES)
		{
			// move previous
			m_nIndexIndex -= 1;

			// check for this item by index, no error reporting
			// if found, display info, if not treat as new index
			if (getIndexInfo(m_pTableDef, &m_II, m_nIndexIndex, FALSE))
			{
				// list ctrl should be cleared and then set to new values for this index
				setFieldListSelections(FALSE);

				// most properties are readonly once a field is in a collection
				disableControlsForExisting(TRUE);
			}
			else
			{
				// initialize field property values for new field
				indexInitializer();

				// list box should be cleared
				setFieldListSelections(TRUE);

				// new field have read/write properties
				disableControlsForExisting(FALSE);
			}

			// update the dialog controls with new values
			UpdateData(FALSE);
		}
	}

	// set focus to name of field edit box
	CEdit *pEdit = (CEdit *)GetDlgItem(IDC_INDEX_NAME);
	pEdit->SetFocus();
}

// user selected the "done" button--no more indexes to add/view.  The only
// risk is losing an index that is under construction--check for that
void CAddIndexDlg::OnDone()
{
	// set default to "ready to exit dialog"
	int retCode = IDYES;

	// if user has entered an index name, then warn them they will lose
	// it if it is not explicitly added--we don't want to do an auto-add
	// since user may have entered name without meaning to add another index
	//
	// see if there is a index name specified
	CString name;
	CEdit *pEdit = (CEdit *)GetDlgItem(IDC_INDEX_NAME);
	pEdit->GetWindowText(name);
	// if there is a name, then warn the user
	if (name.GetLength() != 0)
	{
		// only an issue if this is not an existing index
		if (!IsExistentIndex(m_pTableDef, name))
			retCode = AfxMessageBox(_T("Current index will be ignored unless added.  Continue anyway?"),
								MB_YESNO);
	}

	// either there never was a index name specified or the user has
	// chosen not to add the index
	if (retCode == IDYES)
	{
		// done with tabledef object
		delete m_pTableDef;

		// end the dialog
		CDialog::EndDialog(0);
	}
}

// user selected to exit the dialog--don't do any
// checking for loss of newly specified indexes
void CAddIndexDlg::OnClose()
{
	// close the tabledef if it is open
	if (m_pTableDef->IsOpen())
		m_pTableDef->Close();

	// clean up
	delete m_pTableDef;

	CDialog::OnClose();
}

// user wants to add the specified index to the collection
void CAddIndexDlg::OnAddIndex()
{
	// get values from control -- don't continue if failure
	if (!UpdateData(TRUE))
		return;

	// don't do anything if this is an existing index (except
	// say so)
	if (!IsExistentIndex(m_pTableDef, m_II.m_strName))
	{
		// must create the fields that are in the index
		createFieldArray(&(m_II.m_pFieldInfos), &(m_II.m_nFields));

		// try to create the index with error checking--may fail if a
		// duplicate named index already exists. Note: creating an index
		// also appends it to the tabledef's index collection
		if (!createNewIndex(m_pTableDef, &m_II))
			return;

		// clean out all properties
		indexInitializer();

		// list constrol should be cleared
		setFieldListSelections(TRUE);

		// performs visible clearing of controls that are initialized
		UpdateData(FALSE);

		// move to next field index
		m_nIndexIndex += 1;
	}
	else
	{
		AfxMessageBox(_T("Can't add index--it already exists in the TableDef."));
	}

	// set focus to name of index edit box
	CEdit *pEdit = (CEdit *)GetDlgItem(IDC_INDEX_NAME);
	pEdit->SetFocus();
}

// user selected to delete the current index--prompt for acceptance
void CAddIndexDlg::OnDeleteIndex()
{
	// get values from control -- don't continue if failure
	if (!UpdateData(TRUE))
		return;

	// can only delete existing indexes
	if (IsExistentIndex(m_pTableDef, m_II.m_strName))
	{
		// is user sure?
		if (IDYES == AfxMessageBox(_T("Delete current index?"), MB_YESNO))
		{
			// only react if field is deleted!
			if (deleteIndex(m_pTableDef, m_II.m_strName))
			{
				// index into collection is unchanged, so
				// get the information for this index if there is one
				// (no error reporting)
				if (getIndexInfo(m_pTableDef, &m_II, m_nIndexIndex, FALSE))
				{
					// list control should be cleared and then set to reflect new index
					setFieldListSelections(FALSE);

					// disable user selections
					disableControlsForExisting(TRUE);
				}
				else
				{
					// there is no index in collection following the
					// deletion at this collection index, so
					// set the index info to initial state
					indexInitializer();

					// list control should be cleared
					setFieldListSelections(TRUE);

					// enable user selections
					disableControlsForExisting(FALSE);
				}

				// update the dialog controls to erase deleted field
				UpdateData(FALSE);
			}
		}
	}

	// set focus to name of field edit box
	CEdit *pEdit = (CEdit *)GetDlgItem(IDC_INDEX_NAME);
	pEdit->SetFocus();
}


// since most index properties become read-only once the index
// is added to a collection, manage the controls on the dialog
// appropriate to whether this is an existing index or not
void CAddIndexDlg::disableControlsForExisting(BOOL bDisable/* = TRUE*/)
{
	m_UniqueControl.EnableWindow(!bDisable);
	m_RequiredControl.EnableWindow(!bDisable);
	m_IgnoreNullControl.EnableWindow(!bDisable);
	m_PrimaryControl.EnableWindow(!bDisable);

	// set the name edit to read-only
	CEdit *pEdit = (CEdit *)GetDlgItem(IDC_INDEX_NAME);
	pEdit->SetReadOnly(bDisable);
}

// populate the list control with the fields in the field collection of
// the current tabledef
void CAddIndexDlg::populateFieldList()
{
	// struct for getting field information
	CDaoFieldInfo fieldInfo;
	// loop controls and index into the field collection
	BOOL bContinue = TRUE;
	int itemIndex = 0;

	// until we run out of items in the field collection, keep adding items
	for (int i = 0; bContinue; i++)
	{
		// try to get info on the ith field -- no error reporting as specified by last
		// parameter being FALSE
		if (getFieldInfo(m_pTableDef, &fieldInfo, i, FALSE))
		{
			// if this is an indexable field type, then display it
			if ((fieldInfo.m_nType != dbLongBinary) &&
				(fieldInfo.m_nType != dbMemo))
			{
				// insert the name into the list view item, clear the subitem text
				m_FieldListListControl.InsertItem(itemIndex, fieldInfo.m_strName);
				m_FieldListListControl.SetItemText(itemIndex, 1, _T(""));

				// move to next index into the collection
				itemIndex += 1;
			}
		}
		else    // once we fail to get info on an item in the collection, stop the loop
			bContinue = FALSE;
	}
}

// for every item selected in the list control, create an index field info
// struct with the pertinent info and add it to the list of such
// structures
void CAddIndexDlg::createFieldArray(CDaoIndexFieldInfo **ppFields, short *pnFields)
{
	// get maximum count of items in the list control
	int limit = m_FieldListListControl.GetItemCount();

	// if array isn't initialized, delete it, then allocate a new one
	if ((*ppFields) != NULL)
		delete [] (*ppFields);

	// allocate at maximum size although we probably won't use all
	// just for simplicity's sake!
	(*ppFields) = new CDaoIndexFieldInfo[limit];

	// keep track of how many items selected and loop through all items
	(*pnFields) = 0;
	for (int i = 0; i < limit; i++)
	{
		// if selected, get the name of the field (selection indicated by
		// non-empty subitem string)
		if (m_FieldListListControl.GetItemText(i, 1) != _T(""))
		{
			// put the name into the array
			(*ppFields)[(*pnFields)].m_strName = m_FieldListListControl.GetItemText(i, 0);

			// put the sort order into the array as a boolean
			(*ppFields)[(*pnFields)].m_bDescending =
						(m_FieldListListControl.GetItemText(i, 1) == _T("descending"));

			// up the count by one
			(*pnFields) += 1;
		}
	}
}

// make the list control reflect which fields make up the current index
//
// IN: bJustClear-by default, clear AND make selection in the list control, but
//     you can specify to just clear the control of all selections
//
void CAddIndexDlg::setFieldListSelections(BOOL bJustClear /* = FALSE*/)
{
	// get maximum number of items in list
	int numStrings = m_FieldListListControl.GetItemCount();
	int selection;

	// reset any current selections
	for (int i = 0; i < numStrings; i++)
	{
		m_FieldListListControl.SetItemState(i, 0, LVIS_SELECTED);
		m_FieldListListControl.SetItemText(i, 1, _T(""));
	}

	// this function can be called to simply clear the list control
	// of selections or you can reflect the current index selections too
	if (!bJustClear)
	{
		// select the appropriate items--set up the finder struct
		LV_FINDINFO lvfi;
		lvfi.flags = LVFI_STRING;   // searching for strings
		CString strSort;            // used to create string to indicate sort direction

		// for all items in the index info struct, find and set the items
		for (int i = 0; i < m_II.m_nFields; i++)
		{
			// find the item in the already populated list control--start from the top
			lvfi.psz = m_II.m_pFieldInfos[i].m_strName;
			selection = m_FieldListListControl.FindItem(&lvfi, -1);

			// select the item
			m_FieldListListControl.SetItemState(selection, LVIS_SELECTED, LVIS_SELECTED);

			// set the sort order subitem text appropriately
			strSort = m_II.m_pFieldInfos[i].m_bDescending ? _T("descending") : _T("ascending");
			m_FieldListListControl.SetItemText(selection, 1, strSort);
		}

		UpdateData(FALSE);
	}
}