从列表视图控件中删除一个项目

Question

我的程序中有一个列表视图控件，我想删除所选的项目。 按下按钮即可完成。

问题是，无论我选择什么项目，它始终会删除第一个项目...

我认为问题在于失去了列表视图焦点。 当按下按钮时，列表视图首先失去焦点，然后尝试删除不再选择的项目，因此删除了第一个。

我的问题是：是否可以选择使列表视图不失去其焦点？

编辑：

这是代码：

stdafx.h中

// stdafx.h : include file for standard system include files,
// or project specific include files that are used frequently, but
// are changed infrequently
//

#pragma once

#include "targetver.h"

#define WIN32_LEAN_AND_MEAN    // Exclude rarely-used stuff from Windows headers
// Windows Header Files:
#include <windows.h>
#include <windowsx.h>
#include <commctrl.h>

// C RunTime Header Files
#include <stdlib.h>
#include <malloc.h>
#include <memory.h>
#include <tchar.h>


// TODO: reference additional headers your program requires here

Main.cpp的

#include "stdafx.h"


LRESULT CALLBACK WindowFunc(HWND, UINT, WPARAM, LPARAM);

void CreateList();
void CreateButtons();

enum
{
    IDC_REMOVE_BUTTON = 1000,
    IDC_LIST
};


struct ListBox
{
    HWND hwnd;

    LVCOLUMN lvc;
    LVITEM   lv;

    ListBox(HWND h = 0, LVCOLUMN l = { 0 }, LVITEM lvi = { 0 })
    {
        hwnd = h;
        lvc = l;
        lv = lvi;
    }

};



int selitm = -1;


HINSTANCE g_hInstance;

HWND hwndRemoveButton;

HWND g_hwnd;

ListBox List;





int WINAPI WinMain(HINSTANCE hThisInst, HINSTANCE hPrevInst,
    LPSTR Args, int WinMode)
{
    HWND hWnd;
    MSG Message;
    WNDCLASSEX WinClass = { 0 };
    INITCOMMONCONTROLSEX icc = { 0 };

    g_hInstance = hThisInst;

    icc.dwSize = sizeof(icc);
    icc.dwICC = ICC_LISTVIEW_CLASSES;
    InitCommonControlsEx(&icc);

    WinClass.cbSize = sizeof(WNDCLASSEX);
    WinClass.hInstance = hThisInst;
    WinClass.lpszClassName = "Test";
    WinClass.lpfnWndProc = WindowFunc;
    WinClass.style = 0;
    WinClass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    WinClass.hIconSm = LoadIcon(NULL, IDI_WINLOGO);
    WinClass.hCursor = LoadCursor(NULL, IDC_ARROW);
    WinClass.lpszMenuName = NULL;
    WinClass.cbClsExtra = 0;
    WinClass.cbWndExtra = 0;
    WinClass.hbrBackground = (HBRUSH)COLOR_WINDOW;

    if (!RegisterClassEx(&WinClass)) return 0;

    hWnd = CreateWindow("Test", "Test", WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT, 660, 350,
        NULL, NULL, hThisInst, NULL);

    ShowWindow(hWnd, WinMode);
    UpdateWindow(hWnd);


    while (GetMessage(&Message, NULL, 0, 0))
    {
        TranslateMessage(&Message);
        DispatchMessage(&Message);
    }


    return Message.wParam;
}


LRESULT CALLBACK WindowFunc(HWND hWnd, UINT Message, WPARAM wParam, LPARAM lParam)
{

    switch (Message)
    {
    case WM_CREATE:

        g_hwnd = hWnd;

        CreateList();
        CreateButtons();

        ListView_InsertItem(List.hwnd, &List.lv);
        ListView_SetCheckState(List.hwnd, List.lv.iItem, true);
        ListView_SetItemText(List.hwnd, List.lv.iItem, 1, "One");
        ListView_SetItemText(List.hwnd, List.lv.iItem, 2, "$1");
        ListView_SetItemText(List.hwnd, List.lv.iItem++, 3, "2010-05-05");


        ListView_InsertItem(List.hwnd, &List.lv);
        ListView_SetCheckState(List.hwnd, List.lv.iItem, true);
        ListView_SetItemText(List.hwnd, List.lv.iItem, 1, "Two");
        ListView_SetItemText(List.hwnd, List.lv.iItem, 2, "$2");
        ListView_SetItemText(List.hwnd, List.lv.iItem++, 3, "2008-05-05");


        ListView_InsertItem(List.hwnd, &List.lv);
        ListView_SetCheckState(List.hwnd, List.lv.iItem, false);
        ListView_SetItemText(List.hwnd, List.lv.iItem, 1, "Three");
        ListView_SetItemText(List.hwnd, List.lv.iItem, 2, "$3");
        ListView_SetItemText(List.hwnd, List.lv.iItem++, 3, "2006-05-05");

        break;


    case WM_COMMAND:

        // The low word of wParam contains the menu ID.
        switch (LOWORD(wParam))
        {

        case IDC_REMOVE_BUTTON:

            selitm = ListView_GetFocusedGroup(List.hwnd);

            ListView_DeleteItem(List.hwnd, selitm);

            break;

        }

        break;

    case WM_DESTROY:
        PostQuitMessage(0);
        break;


    default:
        return DefWindowProc(hWnd,
            Message,
            wParam,
            lParam);
    }
    return 0;
}


void CreateButtons()
{
    hwndRemoveButton = CreateWindow("Button", "Remove",
        BS_PUSHBUTTON | WS_CHILD | WS_VISIBLE,
        20, 265, 70, 30,
        g_hwnd, (HMENU)IDC_REMOVE_BUTTON,
        g_hInstance, NULL);
}


void CreateList()
{

    List.hwnd = CreateWindow(WC_LISTVIEW, NULL,
    WS_CHILD | WS_VISIBLE | LVS_REPORT,
    20, 30, 600, 230,
    g_hwnd, (HMENU)IDC_LIST, g_hInstance, NULL);

    ListView_SetExtendedListViewStyle(List.hwnd, LVS_EX_CHECKBOXES | LVS_EX_FULLROWSELECT | LVS_EX_HEADERDRAGDROP);

    List.lvc.mask = LVCF_TEXT | LVCF_SUBITEM | LVCF_WIDTH | LVCF_FMT;
    List.lvc.fmt = LVCFMT_LEFT;

    /* Add four columns to the list-view (first column contains check box). */
    List.lvc.iSubItem = 0;

    List.lvc.cx = 50;
    List.lvc.pszText = "Good?";
    ListView_InsertColumn(List.hwnd, List.lvc.iSubItem++, &List.lvc);

    List.lvc.cx = 300;
    List.lvc.pszText = "Name";
    ListView_InsertColumn(List.hwnd, List.lvc.iSubItem++, &List.lvc);

    List.lvc.cx = 150;
    List.lvc.pszText = "Cost";
    ListView_InsertColumn(List.hwnd, List.lvc.iSubItem++, &List.lvc);

    List.lvc.cx = 100;
    List.lvc.pszText = "Watched Since";
    ListView_InsertColumn(List.hwnd, List.lvc.iSubItem++, &List.lvc);

    List.lv.iItem = 0;

}

Answer 1

您的问题与重点无关。 您使用了错误的API来确定所选项目。 需要使用ListView_GetNextItem()代替时，您正在使用ListView_GetFocusedGroup() ：

selitm = ListView_GetNextItem(List.hwnd, -1, LVNI_SELECTED);
if (selitm != -1)
    ListView_DeleteItem(List.hwnd, selitm);

Answer 2

您正在调用ListView_GetFocusedGroup 。 正如所记录的 ：

获取具有焦点的组

组是列表视图的高级功能。 再次，如记录所示 ：

分组允许用户使用水平分隔符和组标题将列表排列为在页面上可视地划分的项目组。

因此，这不是您想要的。 您需要获取所选项目的API是ListView_GetNextItem 。 这样称呼它：

int selectedIndex = ListView_GetNextItem(List.hwnd, -1, LVNI_ALL | LVNI_SELECTED);
if (selectedIndex != -1)
    ListView_DeleteItem(List.hwnd, selitm);