win32 ListView Custom Draw，为什么dwDrawStage值总是等于1

Question

我正在做win32 listview控件，想实现CustomDraw，

但我发现了一些奇怪的事情。我想知道为什么这个 dwDrawStage 值总是等于 1

bool rst = CreateWinEx(WC_LISTVIEW, NULL,
        WS_CHILD | WS_VISIBLE | LVS_REPORT | LVS_EDITLABELS  | LVS_NOCOLUMNHEADER | WS_BORDER,0,
        x,y,w,h,
        hwndParent_, NULL, GetModuleHandle(NULL));

OnListViewNotify

LRESULT my::listView::OnListViewNotify(HWND hwnd,LPARAM lParam)
{

    NMLISTVIEW* pnmv= (NMLISTVIEW*)lParam;

    LRESULT lResult = 0;

    switch(pnmv->hdr.code)
    {
        case  NM_CUSTOMDRAW:
        {
            idebug("NM_CUSTOMDRAW\n");
            SetWindowLong(hWnd, DWL_MSGRESULT, (LONG)CustomDraw(lParam));
            return TRUE;
        }
        break;
    }
    return(lResult);
}

自定义绘图

LRESULT  my::listView::CustomDraw( LPARAM lParam )
{
    //NMLVCUSTOMDRAW* pLVCD = reinterpret_cast<NMLVCUSTOMDRAW*>( pNMHDR );
    LPNMLVCUSTOMDRAW pLVCD = (LPNMLVCUSTOMDRAW) lParam;
    
    idebug("dwDrawStage:%d\n",pLVCD->nmcd.dwDrawStage);

     switch(pLVCD->nmcd.dwDrawStage) 
    {
        case CDDS_PREPAINT:
        {
            //request notifications for individual listview items
            return CDRF_NOTIFYITEMDRAW;
        }    
        case CDDS_ITEMPREPAINT: //Before an item is drawn
        {
            return CDRF_NOTIFYSUBITEMDRAW;
        }
        case CDDS_SUBITEM | CDDS_ITEMPREPAINT: //Before a subitem is drawn
        {
            switch(pLVCD->iSubItem)
            {
                case 0:
                {
                    pLVCD->clrText   = RGB(255,255,255);
                    pLVCD->clrTextBk = RGB(240,55,23);
                    return CDRF_NEWFONT;

                }
                case 1:
                {
                    pLVCD->clrText   = RGB(255,255,0);
                    pLVCD->clrTextBk = RGB(0,0,0);
                    return CDRF_NEWFONT;
                }
            }
        }
    }
    return CDRF_DODEFAULT;
}

想实现CustomDraw，但是我遇到了一些奇怪的事情。我想知道为什么这个 dwDrawStage 值总是等于 1

来自调试的信息

hdr.code->NM_CUSTOMDRAW
dwDrawStage:1

感谢您分享您的智慧和经验；

Answer 1

正如@Adrian Mole 所说，关键是关于 return 值。

当我 return CDRF_NEWFONT 或 return CDRF_NOTIFYITEMDRAW 时问题消失了。

win32 ListView Custom Draw，为什么dwDrawStage值总是等于1

win32 ListView CustomDraw , why dwDrawStage value is alway equal to 1

listview

winapi

custom-draw