MFC

Question

在运行时，我正在尝试创建单列自定义 CListCtrl（或 CMFCListCtrl，但不是 CheckListBox - 我希望能够在未来）使用 MFC。使用 LVS_EX_CHECKBOXES 样式会强制所有项目都具有复选框。所需的控件应如下所示（item1 和 item3 有复选框，item2 没有）：

从用户的角度来看，应该像这样创建所需的列表控件：

int main() {
    MyCListCtrl list_control;
    list_control.AddItem("item1", true) // true indicates checkbox presence
    list_control.AddItem("item2", false) // false - item without checkbox
    list_control.AddItem("item3", true) // true indicates checkbox presence
}

到目前为止，我能够创建这样的控件，但是添加 LVS_OWNERDRAWFIXED 会触发失败的断言，当调用基础 class CListCtrl::DrawItem 方法时：

    // MyCListCtrl.h
    class MyCListCtrl : public CListCtrl {
    public:
        virtual void DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct) override {
            // if the item should be without a checkbox, here I want to move it a few pixels
            // to the left so that the checkbox is hidden
            ...
            CListCtrl::DrawItem(lpDrawItemStruct); // call base's DrawItem - without this
                                  // there's no exception but the listbox appears empty
        }
    };

    BOOL MyCDialogEx::OnInitDialog() {
        CDialogEx::OnInitDialog();
        ...
        // list being defined somewhere in the header file
        list->Create(WS_CHILD | WS_VISIBLE | WS_BORDER | LVS_REPORT | LVS_NOCOLUMNHEADER |
                                            LVS_OWNERDRAWFIXED, // for DrawItem invocation
                                            rect, this, SOME_ID);
        list->SetExtendedStyle(list->GetExtendedStyle() | LVS_EX_CHECKBOXES);

        // add 1 mandatory column because of LVS_REPORT style
        LVCOLUMN lvColumn;
        lvColumn.mask = LVCF_FMT | LVCF_TEXT | LVCF_WIDTH;
        lvColumn.fmt = LVCFMT_LEFT;
        lvColumn.cx = rect.Width() - 20; // also, how to make this column fit the width exactly?
        lvColumn.pszText = nullptr;
        list->InsertColumn(0, &lvColumn);

        // for now only add 1 testing item and make his checkbox disappear by moving the
        // whole item to the left in DrawItem method (called by the system), so that the text
        // is aligned to the left list border
        list->InsertItem(0, "item1");
        ...
    }

这就是我的（不起作用的）解决方案的样子，如果您知道如何解决这个问题，甚至可能以更简单的方式解决，请告诉我。谢谢。

编辑

在@Landstalker 的帮助下，我现在可以使用自定义绘图擦除复选框，但我仍然需要将文本向左移动（因此它取代了不存在的复选框，如上图）。当前解决方案导致此结果：

这是通过像这样处理 NM_CUSTOMDRAW 消息来实现的：

    void MyCListCtrl::OnCustomDraw(NMHDR* pNMHDR, LRESULT* pResult)
    {
        *pResult = CDRF_DODEFAULT; // default windows painting
        LPNMLVCUSTOMDRAW lpn = (LPNMLVCUSTOMDRAW)pNMHDR;

        if (CDDS_PREPAINT == lpn->nmcd.dwDrawStage)
        {
            *pResult = CDRF_NOTIFYITEMDRAW; // notify on every item
        }
        else if (CDDS_ITEMPREPAINT == lpn->nmcd.dwDrawStage)
        {
            int row = lpn->nmcd.dwItemSpec;
            if (row == 1) {
                lpn->nmcd.rc.left -= 16; // not working
                lpn->rcText.left -= 16; // not working

                SetItemState(row, INDEXTOSTATEIMAGEMASK(0), 
                                  LVIS_STATEIMAGEMASK); // erase checkbox
            }
        }
    }

Answer 1

经过长时间的调查...我为您找到了解决方案：使用 SetItemState () 魔术功能：

Remarque : 有多列不是问题

MyCListCtrl.h

class MyCListCtrl : public CListCtrl 
{
    DECLARE_DYNAMIC(MyCListCtrl)

public:
    afx_msg void DrawItem(NMHDR* pNMHDR, LRESULT* pResult);
    DECLARE_MESSAGE_MAP()
};

MyCListCtrl.cpp

IMPLEMENT_DYNAMIC(MyCListCtrl, CListCtrl)

BEGIN_MESSAGE_MAP(MyCListCtrl, CListCtrl)
    ON_NOTIFY_REFLECT(NM_CUSTOMDRAW, DrawItem)
END_MESSAGE_MAP()

void MyCListCtrl::DrawItem(NMHDR* pNMHDR, LRESULT* pResult)
{
    *pResult = 0;
    LPNMLVCUSTOMDRAW  pLPN = (LPNMLVCUSTOMDRAW)pNMHDR;
    int iRow = pLPN->nmcd.dwItemSpec;

    // Get item flag : true or false (true we show checkbox, false we hide it)
    // Here i simulate, i disable rows 1 and 3
    SetItemState(1, INDEXTOSTATEIMAGEMASK(0), LVIS_STATEIMAGEMASK);
    SetItemState(3, INDEXTOSTATEIMAGEMASK(0), LVIS_STATEIMAGEMASK);

    switch(pLPN->nmcd.dwDrawStage)
    {
    case CDDS_PREPAINT | CDDS_ITEM | CDDS_SUBITEM :
        {
            *pResult = CDRF_DODEFAULT | CDRF_DOERASE; return;
        }
    case CDDS_PREPAINT :
        {
            *pResult = CDRF_NOTIFYITEMDRAW; return;
        }
    case CDDS_ITEMPREPAINT:
        {
            pLPN->clrText = RGB(0,0,0);
            *pResult = CDRF_NOTIFYSUBITEMDRAW;  return;
        }
    }
}

MainDlg.cpp

CRect rect (30, 30, 180, 180);
list_control.Create(WS_CHILD | WS_VISIBLE | LVS_REPORT | LVS_NOCOLUMNHEADER |LBS_OWNERDRAWVARIABLE , rect, this, IDC_LIST2);
list_control.SetExtendedStyle(list_control.GetExtendedStyle() | LVS_EX_FLATSB | LVS_EX_CHECKBOXES | LVS_EX_GRIDLINES);

LVCOLUMN lvColumn;
lvColumn.mask = LVCF_FMT | LVCF_TEXT | LVCF_WIDTH;
lvColumn.fmt = LVCFMT_LEFT;
lvColumn.cx = 70; 
lvColumn.pszText = "Column 1";
list_control.InsertColumn(0, &lvColumn);  

lvColumn.pszText = "Column 2";
list_control.InsertColumn(1, &lvColumn);

//// add 1 test item
LVITEM lvItem;
lvItem.mask = LVIF_TEXT;
lvItem.iItem = 0;
lvItem.iSubItem = 0;
lvItem.pszText = "Test";
list_control.InsertItem(&lvItem);

lvItem.pszText = "Stack";
list_control.InsertItem(&lvItem);

lvItem.pszText = "Over";
list_control.InsertItem(&lvItem);

lvItem.pszText = "Flow";
list_control.InsertItem(&lvItem);

MFC - 带有可选复选框的 CListCtrl 行

MFC - CListCtrl rows with optional checkboxes

c++

clistctrl

clistbox