virtual int CharToItem( UINT nKey, UINT nIndex );
Return Value
Returns – 1 or – 2 for no further action or a nonnegative number to specify an index of a list-box item on which to perform the default action for the keystroke. The default implementation returns – 1.
Parameters
nKey
The ANSI code of the character the user typed.
nIndex
The current position of the list-box caret.
Remarks
This function is called by the framework when the list box's parent window receives a WM_CHARTOITEM message from the list box. The WM_CHARTOITEM message is sent by the list box when it receives a WM_CHAR message, but only if the list box meets all of these criteria:
You should never call this function yourself. Override this function to provide your own custom handling of keyboard messages.
In your override, you must return a value to tell the framework what action you performed. A return value of – 1 or – 2 indicates that you handled all aspects of selecting the item and requires no further action by the list box. Before returning – 1 or – 2, you could set the selection or move the caret or both. To set the selection, use SetCurSel or SetSel. To move the caret, use SetCaretIndex.
A return value of 0 or greater specifies the index of an item in the list box and indicates that the list box should perform the default action for the keystroke on the given item.
Example
// CMyListBox is my owner-drawn list box derived from CListBox. This
// example moves the caret down one item on a numeric key and up one item
// on an alphabetic key. The list box control was created with the
// following code:
// pmyListBox->Create(
// WS_CHILD|WS_VISIBLE|WS_BORDER|WS_HSCROLL|WS_VSCROLL|
// LBS_SORT|LBS_MULTIPLESEL|LBS_OWNERDRAWVARIABLE|LBS_WANTKEYBOARDINPUT,
// CRect(10,10,200,200), pParentWnd, 1);
//
int CMyListBox::CharToItem(UINT nKey, UINT nIndex)
{
// On a numeric key, move the caret up one item.
if (isdigit(nKey) && (nIndex > 0))
SetCaretIndex(nIndex-1);
// On an alphabetic key, move the caret down one item.
else if (isalpha(nKey) && (nIndex < GetCount()))
SetCaretIndex(nIndex+1);
// Do not perform any default processing.
return -1;
}
CListBox Overview | Class Members | Hierarchy Chart
See Also CListBox::VKeyToItem, CListBox::SetCurSel, CListBox::SetSel, CListBox::SetCaretIndex, WM_CHARTOITEM