一、說明
家都知道在MFC中通過給CListCtrl設(shè)置LVS_EDITLABELS屬性,并且在程序中響應(yīng)控件的LVN_ENDLABELEDIT消息可以修改列表控件每一行的第一項(xiàng),也就是主項(xiàng)(Item)。代碼如下:
void CEditListCtrlSampleDlg::OnEndlabeleditList1(NMHDR* pNMHDR, LRESULT* pResult)
{
LV_DISPINFO* pDispInfo = (LV_DISPINFO*)pNMHDR;
// TODO: Add your control notification handler code here
*pResult = TRUE; //TRUE值表示可以修改主項(xiàng),F(xiàn)ALSE值表示不修改主項(xiàng)
}但是讓人郁悶的是,微軟留了一手,CListCtrl不支持直接修改子項(xiàng)(SubItem)。無奈之下只好自力更生,對CListCtrl進(jìn)行擴(kuò)展。>_<!!!!
二、原理
通過在浩如煙海的互聯(lián)網(wǎng)上查找資料(當(dāng)然包括了名鼎鼎的VCKBASE),發(fā)現(xiàn)現(xiàn)有的實(shí)現(xiàn)都是對子項(xiàng)鼠標(biāo)單擊一次就可以編輯。但本人對CListCtrl的單擊一次高亮文本,再單擊一次才開始編輯的操作模式感覺比較喜歡,所以就有了這篇文章的誕生。
要想實(shí)現(xiàn)高亮文本也就是對文本進(jìn)行著色處理,這可以通過對NM_CUSTOMDRAW消息進(jìn)行處理實(shí)現(xiàn),提示類向?qū)е袥]有這個(gè)消息映射只能進(jìn)行手工添加。
要想編輯文本則可以通過EditLabel(int nItem)成員函數(shù)以及對LVN_BEGINLABELEDIT和LVN_ENDLABELEDIT的消息處理實(shí)現(xiàn)。
三、實(shí)現(xiàn)
本文最終實(shí)現(xiàn)的CEditListCtrl擴(kuò)展類在盡量符合CListCtrl操作步驟的情況下實(shí)現(xiàn)對主項(xiàng)及子項(xiàng)的可編輯。
成員變量說明:
int m_iItem; //主項(xiàng)標(biāo)識符
int m_iSubItem; //子項(xiàng)標(biāo)識符
BOOL m_bFocus; //是否繪制項(xiàng)文本焦點(diǎn)框
BOOL m_bHighLight; //是否高亮項(xiàng)文本
CItemEdit m_edtItemEdit; //用于子類化EditLabel函數(shù)返回的CEdit*指針
列表控件中所有項(xiàng)文本的繪制以及特效(焦點(diǎn)框、高亮)都在NM_CUSTOMDRAW消息處理中實(shí)現(xiàn):
void CEditListCtrl::OnCustomDraw(NMHDR* pNMHDR, LRESULT* pResult)
{
NMLVCUSTOMDRAW* pNMLVCustomDraw = (NMLVCUSTOMDRAW*)pNMHDR;
// Take the default processing unless we set this to something else below.
*pResult = CDRF_DODEFAULT;
// First thing - check the draw stage. If it's the control's prepaint
// stage, then tell Windows we want messages for every item.
if (pNMLVCustomDraw->nmcd.dwDrawStage == CDDS_PREPAINT)
{
*pResult = CDRF_NOTIFYITEMDRAW;
}
else if (pNMLVCustomDraw->nmcd.dwDrawStage == CDDS_ITEMPREPAINT)
{
// This is the notification message for an item. We'll request
// notifications before each subitem's prepaint stage.
*pResult = CDRF_NOTIFYSUBITEMDRAW;
}
else if (pNMLVCustomDraw->nmcd.dwDrawStage == (CDDS_ITEMPREPAINT | CDDS_SUBITEM))
{
//當(dāng)前要繪制的主項(xiàng)標(biāo)識符和子項(xiàng)標(biāo)識符
int iItem = (int)pNMLVCustomDraw->nmcd.dwItemSpec;
int iSubItem = pNMLVCustomDraw->iSubItem;
CDC* pDC = CDC::FromHandle(pNMLVCustomDraw->nmcd.hdc);
CString strItemText = GetItemText(iItem, iSubItem);
CRect rcItem, rcText;
GetSubItemRect(iItem, iSubItem, LVIR_LABEL, rcItem);
rcText = rcItem;
CSize size = pDC->GetTextExtent(strItemText);
if(strItemText == _T(""))
{
size.cx = 41;
}
//設(shè)置文本高亮矩形
rcText.left += 4;
rcText.right = rcText.left + size.cx + 6;
if(rcText.right > rcItem.right)
{
rcText.right = rcItem.right;
}
COLORREF crOldTextColor = pDC->GetTextColor();
//繪制項(xiàng)焦點(diǎn)/高亮效果
if(m_bFocus)
{
if((m_iItem == iItem) && (m_iSubItem == iSubItem))
{if(m_bHighLight)
{pDC->SetTextColor(::GetSysColor(COLOR_HIGHLIGHTTEXT));
pDC->FillSolidRect(&rcText, ::GetSysColor(COLOR_HIGHLIGHT));
}
pDC->DrawFocusRect(&rcText);
}}
//繪制項(xiàng)文本
rcItem.left += 6;
pDC->DrawText(strItemText, &rcItem, DT_LEFT | DT_VCENTER | DT_SINGLELINE | DT_END_ELLIPSIS | DT_NOCLIP);
pDC->SetTextColor(crOldTextColor);
*pResult = CDRF_SKIPDEFAULT;// We've painted everything.
}}單擊一次文本高亮,再單擊一次文本開始編輯在WM_LBUTTONDOWN消息處理中實(shí)現(xiàn):void CEditListCtrl::OnLButtonDown(UINT nFlags, CPoint point)
{
m_bFocus = TRUE;
LVHITTESTINFO lvhit;
lvhit.pt = point;
int item = SubItemHitTest(&lvhit);
//if (over a item/subitem)
if (item != -1 && (lvhit.flags & LVHT_ONITEM))
{
CListCtrl::OnLButtonDown(nFlags, point);
if(m_bHighLight && m_iItem == lvhit.iItem && m_iSubItem == lvhit.iSubItem)
{
//第二次單擊
EditLabel(m_iItem);
return;
}
else
{
//第一次單擊
m_iItem = lvhit.iItem;
m_iSubItem = lvhit.iSubItem;
m_bHighLight = TRUE;
}
}
else
{
if(m_edtItemEdit.m_hWnd == NULL)
{
//未出現(xiàn)文本編輯框時(shí)
m_bHighLight = FALSE;
}
CListCtrl::OnLButtonDown(nFlags, point);
}
Invalidate(); //強(qiáng)制重繪控件
}關(guān)鍵的一步,對項(xiàng)文本進(jìn)行編輯。在以上代碼中當(dāng)執(zhí)行到EditLabel時(shí)將會(huì)產(chǎn)生一個(gè)編輯框,這時(shí)需要將它進(jìn)行子類化處理,以控制它出現(xiàn)的位置。void CEditListCtrl::OnBeginlabeledit(NMHDR* pNMHDR, LRESULT* pResult)
{
LV_DISPINFO* pDispInfo = (LV_DISPINFO*)pNMHDR;
if (m_iSubItem >= 0)
{
ASSERT(m_iItem == pDispInfo->item.iItem);
CRect rcSubItem;
GetSubItemRect( pDispInfo->item.iItem, m_iSubItem, LVIR_BOUNDS, rcSubItem);
//get edit control and subclass
HWND hWnd= (HWND)SendMessage(LVM_GETEDITCONTROL);
ASSERT(hWnd != NULL);
VERIFY(m_edtItemEdit.SubclassWindow(hWnd));
//move edit control text 4 pixel to the right of org label,
//as Windows does it...編輯框定位
m_edtItemEdit.m_iXPos = rcSubItem.left + 4;
m_edtItemEdit.SetWindowText(GetItemText(pDispInfo->item.iItem, m_iSubItem));
}
*pResult = 0;
}
void CEditListCtrl::OnEndlabeledit(NMHDR* pNMHDR, LRESULT* pResult)
{
LV_DISPINFO* pDispInfo = (LV_DISPINFO*)pNMHDR;
LV_ITEM*plvItem = &pDispInfo->item;
if (m_iSubItem >= 0)
{
if (plvItem->pszText != NULL )
{
SetItemText(plvItem->iItem,m_iSubItem, plvItem->pszText);
}
VERIFY(m_edtItemEdit.UnsubclassWindow()!=NULL);*pResult = 0;
}
//編輯文本時(shí)對控件父窗口操作(如單擊其它控件)引發(fā)"OnEndlabeledit"時(shí)刷新控件
CRect rect;
GetWindowRect(&rect);
CPoint point;
::GetCursorPos(&point);
if(!rect.PtInRect(point))
{
m_iItem = -1;
m_iSubItem = -1;
m_bFocus = FALSE;
m_bHighLight = FALSE;
}
}通過以上三個(gè)步驟體實(shí)現(xiàn)了本文要達(dá)到的目的,但是還不能放松。接下來還要進(jìn)行一些顯示細(xì)節(jié)方面的處理。這包括對WM_PAINT、WM_SETFOCUS和WM_KILLFOCUS消息的處理,限于篇幅,就不進(jìn)行細(xì)講了,有興趣的朋友可以查看本文提供的源代碼。