如何处理NM_CUSTOMDRAW事件以检索列表项 [英] How To Handle NM_CUSTOMDRAW event to retrieve List items

问题描述

我正在处理Win32/MFC项目.我有一个自定义CListCtrl控件，我必须不时添加一些字符串.我绝对需要对动态添加到CListCtrl的项目执行一些操作.

I'm working on a win32/MFC project. I have a custom CListCtrl control that I must to add, from time to time, some strings of characters. I absolutely need to perform some manipulations on items dynamically added to my CListCtrl.

基本上，我需要:

1. 检测添加单个元素；
2. 检索 _单个项目_立即(理想情况下，InsertItem()调用后不久)；
在地图中
3. 存储单个项目的值，我将使用它们执行其他操作.

1. Detect adding of single elements;
2. Retrieve _single items_ IMMEDIATELY AFTER(ideally, shortly after InsertItem() invocation);
3. Store values of single items in a map, which I will use to perform other manipulations.

我考虑过这样做，以覆盖方法DrawItem().但是OnDraw事件似乎不适用于我的CListCtrl.

I thought about doing this overriding the method DrawItem(). but OnDraw event seems not to be available for my CListCtrl.

永远不会生成事件.

重要提示:请注意，MyCustomCListCtrl的"固定绘制"属性设置为" True "，而"查看">"属性设置为报告 NOT .

IMPORTANT: Please note that MyCustomCListCtrl have "On Draw Fixed" property set to True, but "View" property is NOT set as a report.

因此，我决定处理NW_CUSTOMDRAW事件，编写我的CustomDraw处理程序，如此处:

So, I have decided to handle NW_CUSTOMDRAW event, writing my CustomDraw Handler, as explained here and here:

此处，您可以查看另一个代码示例.

Here you can view another code example.

然后，我需要一种从CListCtrl中检索单个itemID的方法.
更确切地说，我需要一种从NMHDR结构中获取单个商品ID的方法.

Then, I need a way to retrieve single itemIDs from my CListCtrl.
More precisely, I need a way to get single item IDs from NMHDR struct.

我该怎么做?我只能获取添加的 LAST 项目的ID.我确信这是我找不到的简单错误.

How can I do this? I am only able to obtain the ID of the LAST item that I have added. I am sure it's a simple mistake I can't find.

下面的代码示例:

包含CList Ctrl的对话框的来源:

Source of Dialog that contains CList Ctrl:

/* file MyDlg.cpp */

#include "stdafx.h"
#include "MyDlg.h"

// MyDlg dialog

IMPLEMENT_DYNAMIC(MyDlg, CDialog)

MyDlg::MyDlg(CWnd* pParent)
    : CDialog(MyDlg::IDD, pParent)
{
}

MyDlg::~MyDlg()
{
}

void MyDlg::DoDataExchange(CDataExchange* pDX)
{
    CDialog::DoDataExchange(pDX);
    DDX_Control(pDX, IDC_LIST1, listView); /* listView is a MyCustomCListCtrl object */
}

BEGIN_MESSAGE_MAP(MyDlg, CDialog)
    ON_BN_CLICKED(IDC_BUTTON1, &MyDlg::OnBnClickedButton1) 
END_MESSAGE_MAP()

BOOL MyDlg::OnInitDialog()
{
    CDialog::OnInitDialog();
    return TRUE;
}

/* OnBnClickedButton1 handler add new strings to MyCustomCListCtrl object */

void MyDlg::OnBnClickedButton1()
{
    listView.InsertItem(0, "Hello,");
    listView.InsertItem(1, "World!");
}

我的自定义CList Ctrl来源:

My Custom CList Ctrl source:

/* file MyCustomCListCtrl.cpp */

#include "stdafx.h"
#include "MyCustomCListCtrl.h"

MyCustomCListCtrl::MyCustomCListCtrl()
{
}

MyCustomCListCtrl::~MyCustomCListCtrl()
{
}

BEGIN_MESSAGE_MAP(MyCustomCListCtrl, CListCtrl)
    //{{AFX_MSG_MAP(MyCustomCListCtrl)
    //}}AFX_MSG_MAP
    // ON_WM_DRAWITEM()                             /* WM_DRAWITEM NON-AVAILABLE */
    ON_NOTIFY_REFLECT(NM_CUSTOMDRAW, OnCustomDraw)
END_MESSAGE_MAP()

// 'Owner Draw Fixed' property is already TRUE
/*  void CTranslatedCListCtrl::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct)
{
    bool inside = true; /* Member function removed: I never enter here... */
}  */

void MyCustomCListCtrl::OnCustomDraw(NMHDR* pNMHDR, LRESULT* pResult)
{
    /* Here, I must retrieve single strings added to my MyCustomCListCtrl object */

    LPNMLISTVIEW plvInfo = (LPNMLISTVIEW)pNMHDR;
    LVITEM lvItem;

    lvItem.iItem = plvInfo->iItem;          /* Here I always get _the same_ ID: ID of last element...*/
    lvItem.iSubItem = plvInfo->iSubItem;    // subItem not used, for now...

    int MyID = 0;

    this->GetItem(&lvItem); // There mai be something error here?
    MyID = lvItem.iItem;

    CString str = this->GetItemText(MyID, 0); /* ...due to previous error, here I will always get the last string I have added("World!") */

    // Immediately after obtaining ALL IDS, I can Do My Work

    *pResult = 0;
}

感谢您的帮助！

P.S.请不要给我这样的提示:

P.S. Please do not give me tips like:

1. 将固定的自画"属性设置为True；
2. 检查是否已插入"ON_WMDRAWITEM()"行
3. 将您的CListCtrl转换为报告；

我已经尝试了所有方法...:-)

I have already tried everything... :-)

谢谢大家！

IT

推荐答案

首先...谢谢您浪费宝贵的时间解决这个愚蠢问题.我从未发现有关 LVN_INSERT 事件的任何信息.我写科学软件(大部分在Linux平台上)；我不是长期的Win32开发人员，所以我不了解Win32 API.正如您所建议的，我已经修改了 MyCustomCListCtrl 类的源文件.下面的代码似乎是实现我想要的最好(更快)的方式:

first of all... Thank you wasted your precious time with this stupid question. I never found anything about LVN_INSERT event. I write scientific software(most on Linux platform); I am not a long-time Win32 developer, so I don't know Win32 APIs in depth. I have modified source file of MyCustomCListCtrl class, as you have suggested. Code below seems to be the best( and faster )way to achieve what I want:

    /* file MyCustomCListCtrl.cpp */

    #include "stdafx.h"
    #include "MyCustomCListCtrl.h"

    MyCustomCListCtrl::MyCustomCListCtrl()
    {
    }

    MyCustomCListCtrl::~MyCustomCListCtrl()
    {
    }

    BEGIN_MESSAGE_MAP(MyCustomCListCtrl, CListCtrl)
        //{{AFX_MSG_MAP(MyCustomCListCtrl)
        //}}AFX_MSG_MAP
        ON_NOTIFY_REFLECT(LVN_INSERTITEM, OnLvnInsertItem)
    END_MESSAGE_MAP()

    ...

    afx_msg void CTranslatedListCtrl::OnLvnInsertItem(NMHDR* pNMHDR, LRESULT* pResult)
    {
        LPNMLISTVIEW plvInfo = (LPNMLISTVIEW)pNMHDR;
        CString str = this->GetItemText(plvInfo->iItem, 0);

        // Add Some Logic

        *pResult = 0;
    }

您可以确认吗?从我所看到的，它似乎有效.:-)再次感谢！

Can You confirm? From what I can see, it seems to work. :-) Thanks again!

IT

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