第9章 子窗口控件_9.4-9.6滚动条类、编辑框类、列表框类

9.4 滚动条类

9.4.1 滚动条控件

（1）窗口滚动条与滚动条控件的比较

	窗口滚动条	滚动条控件
消息	发送WM_VSCROLL、WM_HSCROLL消息。不发送WM_COMMAND消息。wParam参数的意义是一样的。lParam：当消息来自窗口滚动条时为NULL，来自滚动条控件时为滚动条的句柄。
宽度或高度	固定大小 //水平滚动条高度 GetSysMetrics（SM_CYHSCROLL）; //垂直滚动条宽度 GetSysMetrics（SM_CYVSCROLL）	1、大小、位置均可设定； 2、在CreateWindow或MoveWindow函数中指定，大小可自定义。
窗口样式	WS_VSCROLL：垂直滚动条（在窗口右侧） WS_HSCROLL：水平滚动条（在窗口下方）	可用滚动条样式和尺寸 SBS_VERT、SBS_HORZ、 S SBS_TOPALIGN、  BS_BOTTOMALIGN、SBS_LEFTALIGN、SBS_RIGHTALIGN等。
调用函数 的参数	SetScrollInfo(hwnd,SB_VERT, &si,bRedraw);	SetScrollInfo(hwndScroll,SB_CTL, &si,bRedraw);

（2）滚动条的颜色

①滚动条两端的按钮及滑块：COLOR_BTNFACE、COLOR_BTNHILIGHT、COLOR_BTNSHADOW、COLOR_BTNTEXT（给小箭头用）、COLOR_DKSHADOW及COLOR_BTNLIGHT

②两端按钮之间的大片区域：COLOR_BTNFACE、COLOR_BTNHIGHLIGHT的某种组合。

9.4.2 COLORS1程序

（1）窗口子类化

①用自定义窗口过程（ScrollProc）替换Windows的内部窗口过程

   OldScroll[i]=(WNDPROC)SetWindowLong(hwndScroll[i], GWL_WNDPROC, (LONG)ScrollProc);

②调用旧的滚动条窗口过程

CallWindowProc(OldScroll[id],hwnd, message, wParam, lParam);

（2）主窗口背景着色

      ①准备好背景画刷：新建画刷→存入窗口类结构→删除旧画刷

         DeleteObject((HBRUSH)

               SetClassLong(hwnd, GCL_HBRBACKGROUND,(LONG)

                       CreateSolidBrush(RGB(color[0],color[1], color[2]))));

②终止程序时清除画刷

   DeleteObject((HBRUSH)

        SetClassLong(hwnd, GCL_HBRBACKGROUND,(LONG)GetStockObject(WHITE_BRUSH)));

（3）滚动条和静态文本着色

    ①3个滚动条背景色：hBrush[i] = CreateSolidBrush(crPrim[i]);

    ②在WM_CTLCOLORSCROLLBAR中return (LRESULT)hBrush[i]，返回画刷，即可着色。

    ③静态文本在WM_CTLCOLORSTATIC中通过SetBkColor和SetTextColor为文本着色。

【Color1程序】

/*------------------------------------------------------------
COLORS1.C -- Colors Using Scroll Bars
(c) Charles Petzold, 1998
------------------------------------------------------------*/
#include <windows.h>
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
LRESULT ScrollProc(HWND, UINT, WPARAM, LPARAM);
int idFocus; //当前选中的滚动条
WNDPROC OldScroll[3]; //原3个滚动条控件的窗口过程
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
    PSTR szCmdLine, int iCmdShow)
{
    static TCHAR szAppName[] = TEXT("Colors1");
    HWND         hwnd;
    MSG          msg;
    WNDCLASS     wndclass;
    wndclass.style = CS_HREDRAW | CS_VREDRAW;
    wndclass.lpfnWndProc = WndProc;
    wndclass.cbClsExtra = 0;
    wndclass.cbWndExtra = 0;
    wndclass.hInstance = hInstance;
    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
    wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    wndclass.lpszMenuName = NULL;
    wndclass.lpszClassName = szAppName;
    if (!RegisterClass(&wndclass))
    {
        MessageBox(NULL, TEXT("This program requires Windows NT!"),
            szAppName, MB_ICONERROR);
        return 0;
    }

    hwnd = CreateWindow(szAppName,                  // window class name
        TEXT("Color Scroll1"), // window caption
        WS_OVERLAPPEDWINDOW,        // window style
        CW_USEDEFAULT,              // initial x position
        CW_USEDEFAULT,              // initial y position
        CW_USEDEFAULT,              // initial x size
        CW_USEDEFAULT,              // initial y size
        NULL,                       // parent window handle
        NULL,                       // window menu handle
        hInstance,                  // program instance handle
        NULL);                     // creation parameters

    ShowWindow(hwnd, iCmdShow);
    UpdateWindow(hwnd);

    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return msg.wParam;
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    static COLORREF crPrim[3] = { RGB(255, 0, 0), RGB(0, 255, 0), RGB(0, 0, 255) };
    static HBRUSH hBrush[3], hBrushStatic;//三个滚动条的背景画刷
    static HWND hwndScroll[3], hwndLabel[3], hwndValue[3], hwndRect;
    static TCHAR* szColorLabel[] = { TEXT("Red"), TEXT("Green"), TEXT("Blue") };
    TCHAR szBuffer[10];
    static int cxChar, cyChar;
    HINSTANCE hInstance;
    static RECT     rcColor;
    static int color[3]; //三个滚动条当前的颜色值
    int i, cxClient, cyClient;
    switch (message)
    {
    case WM_CREATE:
        //hInstance = ((LPCREATESTRUCT)lParam)->hInstance;
        hInstance = (HINSTANCE)GetWindowLong(hwnd, GWL_HINSTANCE);
        //创建一个白色矩形区，用来放置控件，窗口ID为9.
        hwndRect = CreateWindow(TEXT("static"),
            NULL,
            WS_CHILD | WS_VISIBLE | SS_WHITERECT,
            0, 0, 0, 0,
            hwnd,
            (HMENU)9, hInstance, NULL);
        for (int i = 0; i< 3; i++)
        {
            //创建三个滚动条，范围0-255，ID分别为0,1.2
            hwndScroll[i] = CreateWindow(TEXT("scrollbar"), NULL,
                WS_CHILD | WS_VISIBLE | WS_TABSTOP | SBS_VERT, //垂直，可接受Tab键
                0, 0, 0, 0,
                hwnd,
                (HMENU)i, hInstance, NULL);
            SetScrollRange(hwndScroll[i], SB_CTL, 0, 255, FALSE);
            SetScrollPos(hwndScroll[i], SB_CTL, 0, FALSE);
            //3个颜色名称为"Red"、"Green"、"Blue"的标签，ID分别为3,4,5
            hwndLabel[i] = CreateWindow(TEXT("static"),
                szColorLabel[i],
                WS_CHILD | WS_VISIBLE | SS_CENTER,
                0, 0, 0, 0,
                hwnd,
                (HMENU)(i + 3), hInstance, NULL);
            //3种颜色值的标签，ID分别为6,7,8
            hwndValue[i] = CreateWindow(TEXT("static"),
                TEXT("0"),
                WS_CHILD | WS_VISIBLE | SS_CENTER,
                0, 0, 0, 0,
                hwnd,
                (HMENU)(i + 6), hInstance, NULL);

            //3个滚动条的背景画刷
            hBrush[i] = CreateSolidBrush(crPrim[i]);
            OldScroll[i] = (WNDPROC)SetWindowLong(hwndScroll[i], GWL_WNDPROC, (LONG)ScrollProc);
        }
        hBrushStatic = CreateSolidBrush(GetSysColor(COLOR_BTNHIGHLIGHT));
        cxChar = LOWORD(GetDialogBaseUnits());
        cyChar = HIWORD(GetDialogBaseUnits());
        return 0;
    case WM_SIZE:
        cxClient = LOWORD(lParam);
        cyClient = HIWORD(lParam);
        SetRect(&rcColor, cxClient / 2, 0, cxClient, cyClient);
        MoveWindow(hwndRect, 0, 0, cxClient / 2, cyClient, TRUE);
        for (int i = 0; i < 3; i++)
        {
            //设置滚动条在主窗口大小和位置:宽cxClient/14,高cyClient -4*cyChar;
            MoveWindow(hwndScroll[i], (2 * i + 1)*cxClient / 14, 2 * cyChar, cxClient / 14, cyClient - 4 * cyChar, TRUE);
            MoveWindow(hwndLabel[i], (2 * i + 1)*cxClient / 14, cyChar / 2, cxClient / 14, cyChar, TRUE);
            MoveWindow(hwndValue[i], (2 * i + 1)*cxClient / 14, cyClient - 3 * cyChar / 2, cxClient / 14, cyChar, TRUE);
        }
        SetFocus(hwnd);
        return 0;
    case WM_VSCROLL:
        //获取子窗口ID
        i = GetWindowLong((HWND)lParam, GWL_ID);
        switch (LOWORD(wParam))
        {
        case SB_PAGEDOWN: //每次增长16；
            color[i] += 16;
            break;
        case SB_PAGEUP:
            color[i] -= 16;
            break;
        case SB_LINEDOWN:
            color[i] += 1;
            break;
        case SB_LINEUP:
            color[i] -= 1;
            break;
        case SB_TOP:
            color[i] = 0;
            break;
        case SB_BOTTOM:
            color[i] = 255;
            break;
        case SB_THUMBPOSITION:
        case SB_THUMBTRACK:
            color[i] = HIWORD(wParam);
            break;
        }
        color[i] = max(0, min(255, color[i]));

        SetScrollPos(hwndScroll[i], SB_CTL, color[i], TRUE);
        wsprintf(szBuffer, TEXT("%i"), color[i]); //%i与%d相同
        SetWindowText(hwndValue[i], szBuffer);
        //设置窗口类的背景颜色
        DeleteObject((HBRUSH)
            SetClassLong(hwnd, GCL_HBRBACKGROUND, (LONG)
            CreateSolidBrush(RGB(color[0], color[1], color[2]))));

        InvalidateRect(hwnd, &rcColor, TRUE);
        return 0;
    case WM_CTLCOLORSCROLLBAR: //wParam：DC，lParam：滚动条句柄
        i = GetWindowLong((HWND)lParam, GWL_ID);
        return (LRESULT)hBrush[i]; //须返回画刷句柄
    case WM_CTLCOLORSTATIC://wParam：DC，lParam：静态类文本的句柄
        i = GetWindowLong((HWND)lParam, GWL_ID);
        if (i >= 3 && i <= 8)
        {
            SetBkColor((HDC)wParam, GetSysColor(COLOR_BTNHIGHLIGHT));
            SetTextColor((HDC)wParam, crPrim[i % 3]);
            return (LRESULT)hBrushStatic;
        }
        break;
    case WM_SYSCOLORCHANGE:
        DeleteObject(hBrushStatic);
        hBrushStatic = CreateSolidBrush(GetSysColor(COLOR_BTNHIGHLIGHT));
        return 0;
    case WM_SETFOCUS:
        SetFocus(hwndScroll[idFocus]);
        return 0;

    case WM_DESTROY:
        //将主窗口画刷设为白色
        DeleteObject((HBRUSH)
            SetClassLong(hwnd, GCL_HBRBACKGROUND, (LONG)GetStockObject(WHITE_BRUSH)));
        DeleteObject(hBrushStatic);
        for (int i = 0; i < 3; i++)
            DeleteObject(hBrush[i]);

        PostQuitMessage(0);
        return 0;
    }
    return DefWindowProc(hwnd, message, wParam, lParam);
}
//窗口子类化
LRESULT ScrollProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    int id = GetWindowLong(hwnd, GWL_ID);//获子窗口ID
    switch (message)
    {
    case WM_KEYDOWN:
        if (wParam == VK_TAB)
        {
            SetFocus(GetDlgItem(GetParent(hwnd), (id + 1) % 3));
        }
        break;
    case WM_SETFOCUS:
        idFocus = id;
        break;
    }
    //调用子窗口旧的窗口过程
    return CallWindowProc(OldScroll[id], hwnd, message, wParam, lParam);
}

9.5 编辑类

9.5.1 编辑类的样式

样式	说明
ES_LEFT	文本对齐方式
ES_RIGHT
ES_CENTER
ES_MULTILINE	多行编辑控件
ES_AUTOHSCROLL	默认会自动文本，加这后不会自动换行，要按回车键。
ES_AUTOVSCROLL	垂直滚动条
ES_NOHIDESEL	失去焦，选中时仍高亮显示

9.5.2 编辑控件的通知消息：WM_COMMAND

参数	含义
lParam	子窗口句柄
wParam	LOWORD(wParam)：子窗口ID
	HIWORD(wParam)：通知码	EN_SETFOCUS：得到焦点 EN_KILLFOCUS：失去焦点 EN_CHANGE：   内容改变 EN_UPDATE：   内容己变化 EN_ERRSPACE： 没有空间了 EN_MAXTEXT：  输入超过最大长度 EN_HSCROLL：  水平滚动条被单击 EN_VSCROLL：  垂直滚动条被单击

9.5.3 使用编辑控件

  ①SetWindowText：输入文本

  ②GetWindowText：读取文本

  ③GetWindowTextLength:获得文本长度

9.5.4 传递消息给编辑控件

操作	消息
复制、剪切、 清除、粘贴	SendMessage(hwndEdit,WM_COPY,0,0); SendMessage(hwndEdit,WM_CUT,0,0); SendMessage(hwndEdit,WM_CLEAR,0,0); SendMessage(hwndEdit,WM_PASTE,0,0);
获取选择文本的位置	SendMessage(hwndEdit,EM_GETSEL,(WPARAM&iStart,(LPARAM)&iEND);
选择文本	SendMessage(hwndEdit,EM_SETSEL,iStart,iEnd);
获得行数	iCount = SendMessage(hwndEdit,EM_LINECOUNT,0,0);
编辑缓冲区起点到指定行的位移量	iOffset = SendMessage(hwndEdit,EM_LINELENGTH,iLine,0); //如果iLine =-1，则返回插入符号所在行的位移量。
获到某行的长度	iLength = SendMessage(hwndEdit,EM_LINELENGTH,iLine,0);
复制一行到缓冲区	iLength = SendMessage(hwndEdit,EM_GETLINE,iLine,(LPARAM)szBuffer

【PopPad1程序】

/*------------------------------------------------------------
POPPAD1.C -- Popup Editor using child window edit box
(c) Charles Petzold, 1998
------------------------------------------------------------*/
#include <windows.h>
#define ID_EDIT 1
static TCHAR szAppName[] = TEXT("PopPad1");
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
    PSTR szCmdLine, int iCmdShow)
{

    HWND         hwnd;
    MSG          msg;
    WNDCLASS     wndclass;
    wndclass.style = CS_HREDRAW | CS_VREDRAW;
    wndclass.lpfnWndProc = WndProc;
    wndclass.cbClsExtra = 0;
    wndclass.cbWndExtra = 0;
    wndclass.hInstance = hInstance;
    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
    wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    wndclass.lpszMenuName = NULL;
    wndclass.lpszClassName = szAppName;
    if (!RegisterClass(&wndclass))
    {
        MessageBox(NULL, TEXT("This program requires Windows NT!"),
            szAppName, MB_ICONERROR);
        return 0;
    }

    hwnd = CreateWindow(szAppName,                  // window class name
        TEXT("edit"), // window caption
        WS_OVERLAPPEDWINDOW,        // window style
        CW_USEDEFAULT,              // initial x position
        CW_USEDEFAULT,              // initial y position
        CW_USEDEFAULT,              // initial x size
        CW_USEDEFAULT,              // initial y size
        NULL,                       // parent window handle
        NULL,                       // window menu handle
        hInstance,                  // program instance handle
        NULL);                     // creation parameters

    ShowWindow(hwnd, iCmdShow);
    UpdateWindow(hwnd);

    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return msg.wParam;
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    static HWND hwndEdit;

    switch (message)
    {
    case WM_CREATE:
        hwndEdit = CreateWindow(TEXT("edit"), NULL,
            WS_CHILD | WS_VISIBLE | WS_HSCROLL | WS_VSCROLL |
            WS_BORDER | ES_LEFT | ES_MULTILINE |
            ES_AUTOHSCROLL | ES_AUTOVSCROLL,
            0, 0, 0, 0, hwnd, (HMENU)ID_EDIT,
            ((LPCREATESTRUCT)lParam)->hInstance, NULL);
        return 0;
    case WM_SETFOCUS:
        SetFocus(hwndEdit);
        return 0;
    case WM_COMMAND:
        if (LOWORD(wParam) == ID_EDIT)
        {
            if (HIWORD(wParam) == EN_ERRSPACE ||
                HIWORD(wParam) == EN_MAXTEXT)
            {
                MessageBox(hwnd, TEXT("Edit Control out of space."),
                    szAppName, MB_OK | MB_ICONSTOP);
            }
        }
        return 0;
    case WM_SIZE:
        MoveWindow(hwndEdit, 0, 0, LOWORD(lParam), HIWORD(lParam), TRUE);
        return 0;
    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    }
    return DefWindowProc(hwnd, message, wParam, lParam);
}

9.6 列表框类

键盘操作	单选列表框	多选列表框
空格键	选择光标所在项	切换选中状态
方向键	移动光标和当前的选择	取消以前所选，并移动光标和选中项
翻页键	移动光标，但不移动选择项
字母键	移动和选择以该字母开头的第一项
Ctrl+方向	移动光标，但不移动选中项
Shift+方向		扩展选中项

9.6.1 列表框的样式

样式	含义
LBS_NOTIFY	默认的列表框样式不能发送WM_COMMAND到父窗口，须指定该样式才行
LBS_SORT	排序
LBS_MULTIPLESEL	多选
LBS_NOREDRAW	新增项目默认不会自我更新，可在WM_SETREDRAW中设置
LBS_STANDARD	标准列表框：LBS_NOTIFY|LBS_SORT|WS_VSCROLL|WS_BORDER

 ★设定列表框的宽度：最长字符串长度+滚动条的宽度

 ★设定列表框的高度：1个字符的高度*视图中项目的数量

9.6.2 向列表框中添加字符串

操作	SendMessage： 返回值——LB_ERRSPACE或LB_ERR或LB_OKAY
在列表框最后增加一项	(hwndList,LB_ADDSTRING,0,(LPARAM)szString); //如果LBS_SORT则会插到顺序后相应的位置。
插入到指定位置	hwndList,LB_INSERTSTRING,iIndex,(LPARAM)szString) //当iIndex=-1时，会被添加到最底部。
删除索引位置处的一个字符串	(hwndList,LB_DELETESTRING,iIndex,0);
清除所有项目	(hwndList,LB_RESETCONTENT,iIndex,0);
开关控件重绘标志	(hwndList,WM_SETREDRAW,FALSE,0); (hwndList,WM_SETREDRAW,TRUE,0);

9.6.3 项目的选择和提取

（1）获取列表框项目数量：iCount=SendMessage(hwndList,LB_GETCOUNT,0,0)

（1）单选列表框

单选列表框操作	相应代码
突出选择某项	SendMessage(hwndList,LB_SETCURSEL,iIndex,0); //lParam为-1时，取消选中所有项
根据起始字符选择一项	SendMessage(hwndList,LB_SELECTSTRING,iIndex, (LPARAM)szSerchString); //如果参数iIndex=-1，那么从顶端开始查找。 //返回值：被选中的索引或没有匹配时为LB_ERR
获取当前选中项的索引	iIndex = SendMessage(hwndList,LB_GETCURSEL,0,0)
获取某项字符串长度	iLength = SendMessage(hwndList,LB_GETTEXTLEN,iIndex,0)
读取项目到缓冲区	iLength =SendMessage(hwndList,LB_GETTEXT,iIndex, (LPARAM)szBuffer);

（3）多选列表框（不能使用LB_SETCURSEL,LB_GETCURSEL或LB_SELECTSTRING）

操作	相应代码
设置某项选择状态 （不影响其他项）	SendMessage(hwndList,LB_SETSEL,wParam,iIndex); //wParam非零时，选中并高亮该项，为0时取消选择 //lParam是-1时，在选择和取消所有项之间切换
检查选择状态	iSelect = SendMessage(hwndList,LB_GETSEL,iIndex,0); //iSelect非零，表示选中。为零时，未选中

9.6.4 接收来自列表框的消息

参数	含义
lParam	子窗口句柄
wParam	LOWORD(wParam)：子窗口ID
	HIWORD(wParam)：通知码	LBN_ERRSPACE： 空间不够 LBN_SELCHANGE：当前选择发生变化 LBN_DBLCLK：   双击 LBN_SELCANCEL：取消选择 LBN_SETFOCUS： 得到焦点 LBN_KILLFOCUS：失去焦点

【ENVIRON.C程序】

（1）环境变量格式

（2）获取和释放环境变量块GetEnvironmentStrings、FreeEnvironmentStrings
（3）获取环境变量 GetEnvironmentVariable
效果图：

 

/*------------------------------------------------------------
ENVIRON.C -- Environment List Box
(c) Charles Petzold, 1998
------------------------------------------------------------*/
#include <windows.h>
#define ID_LIST 1
#define ID_TEXT 2
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
    PSTR szCmdLine, int iCmdShow)
{
    static TCHAR szAppName[] = TEXT("Environ");
    HWND         hwnd;
    MSG          msg;
    WNDCLASS     wndclass;
    wndclass.style = CS_HREDRAW | CS_VREDRAW;
    wndclass.lpfnWndProc = WndProc;
    wndclass.cbClsExtra = 0;
    wndclass.cbWndExtra = 0;
    wndclass.hInstance = hInstance;
    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
    wndclass.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
    wndclass.lpszMenuName = NULL;
    wndclass.lpszClassName = szAppName;
    if (!RegisterClass(&wndclass))
    {
        MessageBox(NULL, TEXT("This program requires Windows NT!"),
            szAppName, MB_ICONERROR);
        return 0;
    }

    hwnd = CreateWindow(szAppName,                  // window class name
        TEXT("Environment List Box"), // window caption
        WS_OVERLAPPEDWINDOW,        // window style
        CW_USEDEFAULT,              // initial x position
        CW_USEDEFAULT,              // initial y position
        CW_USEDEFAULT,              // initial x size
        CW_USEDEFAULT,              // initial y size
        NULL,                       // parent window handle
        NULL,                       // window menu handle
        hInstance,                  // program instance handle
        NULL);                     // creation parameters

    ShowWindow(hwnd, iCmdShow);
    UpdateWindow(hwnd);

    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return msg.wParam;
}
void FillListBox(HWND hwndList)
{
    TCHAR *pVarBlock, *pVarCurr, *pVarBeg, *pVarEnd, *pVarName;
    int iLength;
    //获得环境变量的指针
    pVarCurr = pVarBlock = GetEnvironmentStrings();
    while (*pVarCurr)
    {
        if (*pVarCurr != '=')           //跳过无意义的“=::=::”或"=E:=E:ABC"格式的字符串
        {
            pVarBeg = pVarCurr;            //变量名的开始位置。注意环境变量的格式varName=value
            while (*pVarCurr++ != '=');    //扫描到‘=’号
            pVarEnd = pVarCurr - 1;        //pVarCurr指向'='号

            iLength = pVarEnd - pVarBeg;   //变量名的长度
            //分配内存给变量名
            pVarName = calloc(iLength + 1, sizeof(TCHAR)); //变量名加个''结束，所以iLength+1
            CopyMemory(pVarName, pVarBeg, iLength*sizeof(TCHAR));
            pVarName[iLength] = '';    //变量名以''结束
            //将变量名加入到列表框中,并释放内存
            SendMessage(hwndList, LB_ADDSTRING, 0, (LPARAM)pVarName);
            free(pVarName);
        }
        while (*pVarCurr++ != ''); //找字符串的结束符''，并把指针移向下一行开始。
    }
    FreeEnvironmentStrings(pVarBlock);
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    static HWND hwndList, hwndText;
    int cxChar, cyChar;
    int iLength, iIndex;
    TCHAR *pVarName, *pVarValue;
    switch (message)
    {
    case WM_CREATE:
        cxChar = LOWORD(GetDialogBaseUnits());
        cyChar = HIWORD(GetDialogBaseUnits());

        //创建列表框
        hwndList = CreateWindow(TEXT("listbox"), NULL,
            WS_CHILD | WS_VISIBLE | LBS_STANDARD,
            cxChar, cyChar * 3,
            cxChar * 35 + GetSystemMetrics(SM_CXVSCROLL),
            cyChar * 15,
            hwnd, (HMENU)ID_LIST,
            (HINSTANCE)GetWindowLong(hwnd, GWL_HINSTANCE), NULL);

        hwndText = CreateWindow(TEXT("static"), NULL,
            WS_CHILD | WS_VISIBLE | SS_LEFT,
            cxChar, cyChar,
            GetSystemMetrics(SM_CXSCREEN),
            cyChar,
            hwnd, (HMENU)ID_TEXT,
            (HINSTANCE)GetWindowLong(hwnd, GWL_HINSTANCE), NULL);

        FillListBox(hwndList);
        return 0;
    case WM_COMMAND:
        if (LOWORD(wParam) == ID_LIST &&HIWORD(wParam) == LBN_SELCHANGE)
        {
            //获取列表框的中变量名称
            iIndex = SendMessage(hwndList, LB_GETCURSEL, 0, 0);     //获得当前选中项索引
            iLength = SendMessage(hwndList, LB_GETTEXTLEN, iIndex, 0) + 1;//获得文本长度
            pVarName = calloc(iLength, sizeof(TCHAR)); //calloc初始化元素为0
            SendMessage(hwndList, LB_GETTEXT, iIndex, (LPARAM)pVarName); //获取变量名称
            //获取环境变量名称
            iLength = GetEnvironmentVariable(pVarName, NULL, 0); //获得变量值的数据长度，含''
            pVarValue = calloc(iLength, sizeof(TCHAR));
            GetEnvironmentVariable(pVarName, pVarValue, iLength);//获得变量的值
            //将变量的值显示在文本框中
            SetWindowText(hwndText, pVarValue);
            free(pVarValue);
            free(pVarName);
        }
        return 0;
    case WM_SETFOCUS:
        SetFocus(hwndList);
        return 0;
    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    }
    return DefWindowProc(hwnd, message, wParam, lParam);
}

 9.6.5 列出文件：SendMessage(hwndList,LB_DIR,iAttr,(LPARAM)szFileSpec);

（1）文件属性代码iAttr——下列数值的组合的（最后两个位于高字节）

iAttr	属性
DDL_READWRITE (0x0000)	普通文件
DDL_READONLY  (0x0001)	只读文件
DDL_HIDDEN    (0x0002)	隐藏文件
DDL_SYSTEM    (0x0004)	系统文件
DDL_DIRECTORY (0x0010)	子目录
DDL_ARCHIVE   (0x0020)	设置了存档位的文件
DDL_DRIVES    (0x4000)	包括驱动器字符，如形如“[-C-]”
DDL_EXCLUSIVE (0x8000)	只搜索指定值

       ①前缀DDL:Dialog directory list（对话框目录列表）

       ②如果最高位被设置，则只列出具有某种标志的文件：

如只列出自上次备份以来所有被修改过的文件——DDL_EXCLUSIVE|DDL_ARCHIVE

（2）文件列表的排序：（要使用LBS_SORT样式）

文件列表排序	说明
①先列出满足文件限定条件的所有文件名称
②再列子目录名称	A、第一个子目录[..]：用于返回上一级目录，如果己经是根目录没有这东西。 B、其他子目录[SUBDIR] C、该项是可选的
③最后磁盘驱动器清单	A、驱动器清单，形如：[-A-] B、该项也是可选的

 9.6.6 Windows的HEAD程序

（1）窗口子类化

   在ListProc中捕捉WM_KEYDOWN消息，发现VK_RETURN则发送WM_COMMAND(带LBN_DBLCKL)通知码的消息给父窗口。

（2）获取当前目录或设置当前目录

   GetCurrentDirectory(MAX_PATH + 1, szBuffer);//当前目录

   SetCurrentDirectory(szBuffer)；//将当前目录设置为指定的目录

（3）打开文件和关闭文件：

打开文件：HANDLE hFile =CreateFile(…);

读取文件：ReadFile(hFile, buffer, nNumberOfBytesToRead, lpNumberOfBytesRead,NULL);

关闭文件：CloseFile(hFile);

效果图

 

/*------------------------------------------------------------
HEAD.C -- Displays beginning (head) of file
(c) Charles Petzold, 1998
------------------------------------------------------------*/
#include <windows.h>
#define ID_LIST 1
#define ID_TEXT 2
#define MAXREAD 8192
#define DIRATTR  (DDL_READWRITE|DDL_READONLY|DDL_HIDDEN|DDL_SYSTEM|
    DDL_DIRECTORY | DDL_ARCHIVE | DDL_DRIVES)
#define DTFLAG (DT_WORDBREAK|DT_EXPANDTABS|DT_NOCLIP|DT_NOPREFIX)
WNDPROC OldList;
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
LRESULT CALLBACK ListProc(HWND, UINT, WPARAM, LPARAM);
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
    PSTR szCmdLine, int iCmdShow)
{
    static TCHAR szAppName[] = TEXT("head");
    HWND         hwnd;
    MSG          msg;
    WNDCLASS     wndclass;
    wndclass.style = CS_HREDRAW | CS_VREDRAW;
    wndclass.lpfnWndProc = WndProc;
    wndclass.cbClsExtra = 0;
    wndclass.cbWndExtra = 0;
    wndclass.hInstance = hInstance;
    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
    wndclass.hbrBackground = (HBRUSH)(COLOR_BTNFACE + 1);
    wndclass.lpszMenuName = NULL;
    wndclass.lpszClassName = szAppName;
    if (!RegisterClass(&wndclass))
    {
        MessageBox(NULL, TEXT("This program requires Windows NT!"),
            szAppName, MB_ICONERROR);
        return 0;
    }

    hwnd = CreateWindow(szAppName,                  // window class name
        TEXT("head"), // window caption
        WS_OVERLAPPEDWINDOW,        // window style
        CW_USEDEFAULT,              // initial x position
        CW_USEDEFAULT,              // initial y position
        CW_USEDEFAULT,              // initial x size
        CW_USEDEFAULT,              // initial y size
        NULL,                       // parent window handle
        NULL,                       // window menu handle
        hInstance,                  // program instance handle
        NULL);                     // creation parameters

    ShowWindow(hwnd, iCmdShow);
    UpdateWindow(hwnd);

    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return msg.wParam;
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    HDC         hdc;
    PAINTSTRUCT ps;
    static RECT rect; //在客户区指定的地方显示文件的内容
    int i, cxChar, cyChar;
    static HWND hwndList, hwndText;
    static TCHAR szFile[MAX_PATH + 1]; //保存选中的文件名
    TCHAR szBuffer[MAX_PATH + 1];
    static BYTE buffer[MAXREAD];
    static BOOL bValidFile;
    HANDLE hFile;
    switch (message)
    {
    case WM_CREATE:
        cxChar = LOWORD(GetDialogBaseUnits());
        cyChar = HIWORD(GetDialogBaseUnits());
        rect.top = 3 * cyChar;
        rect.left = 25 * cxChar;
        hwndList = CreateWindow(TEXT("listbox"), NULL,
            WS_CHILDWINDOW | WS_VISIBLE | LBS_STANDARD,
            cxChar, 3 * cyChar,
            cxChar * 20 + GetSystemMetrics(SM_CXVSCROLL),
            cyChar * 20,
            hwnd,
            (HMENU)ID_LIST,
            (HINSTANCE)GetWindowLong(hwnd, GWL_HINSTANCE),
            NULL
            );
        GetCurrentDirectory(MAX_PATH + 1, szBuffer); //当前目录
        hwndText = CreateWindow(TEXT("static"), szBuffer,
            WS_CHILDWINDOW | WS_VISIBLE | SS_LEFT,
            cxChar, cyChar, cxChar * MAX_PATH, cyChar,
            hwnd,
            (HMENU)ID_TEXT,
            (HINSTANCE)GetWindowLong(hwnd, GWL_HINSTANCE),
            NULL
            );
        OldList = (WNDPROC)SetWindowLong(hwndList, GWL_WNDPROC, (LONG)ListProc);
        SendMessage(hwndList, LB_DIR, DIRATTR, (LPARAM)TEXT("*.*"));
        return 0;
    case WM_SIZE:
        rect.right = LOWORD(lParam);
        rect.bottom = HIWORD(lParam);
        return 0;
    case WM_SETFOCUS:
        SetFocus(hwndList);
        return 0;
    case WM_COMMAND:
        if (LOWORD(wParam) == ID_LIST && HIWORD(wParam) == LBN_DBLCLK)
        {
            //判断是否选中项目
            if (LB_ERR == (i = SendMessage(hwndList, LB_GETCURSEL, 0, 0)))
                break;
            //获取选中项的文本
            SendMessage(hwndList, LB_GETTEXT, i, (LPARAM)szBuffer);
            //打开文件
            hFile = CreateFile(szBuffer, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, 0, NULL);
            if (INVALID_HANDLE_VALUE != hFile)   //选中项为文件
            {
                CloseHandle(hFile);
                bValidFile = TRUE;
                lstrcpy(szFile, szBuffer); //保存选中项的文件名
                //将文件及路径显示在文本框中
                GetCurrentDirectory(MAX_PATH + 1, szBuffer);
                if (szBuffer[lstrlen(szBuffer) - 1] != '\')
                {
                    lstrcat(szBuffer, TEXT("\"));  //最未尾加个“”
                }
                SetWindowText(hwndText, lstrcat(szBuffer, szFile));
            }
            else
            {
                //选中项为目录或驱动器
                //1、上级目录：[..]
                //2、子目录如：[SubDir]
                //3、驱动器符：[-c-]
                bValidFile = FALSE;
                //判断是否目录
                szBuffer[lstrlen(szBuffer) - 1] = ''; //变成szBuffer变成[SubDir，加个
                if (!SetCurrentDirectory(szBuffer + 1))   //SubDir加上当前目录为新路径。失败，说明选中的是驱动器 
                {
                    szBuffer[3] = ':'; //变成[-c:]
                    szBuffer[4] = '';//变成[-c:
                    SetCurrentDirectory(szBuffer + 2); //将当前路径设为驱动器符，如c:
                }
                //转到子目录或选中的驱动器的根目录下，获取当前路径。
                GetCurrentDirectory(MAX_PATH + 1, szBuffer);
                //显示当前路径
                SetWindowText(hwndText, szBuffer);
                //清空列表框
                SendMessage(hwndList, LB_RESETCONTENT, 0, 0);
                //显示当前目录下的文件及子目录等信息
                SendMessage(hwndList, LB_DIR, DIRATTR, (LPARAM)TEXT("*.*"));
            }

            InvalidateRect(hwnd, NULL, TRUE);
        }
        return 0;
    case WM_PAINT:
        if (!bValidFile) break; //这里不做任何事，交给DefWindowProc处理
        //打开文件
        hFile = CreateFile(szFile, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, 0, NULL);
        if (INVALID_HANDLE_VALUE == hFile)   //打开文件失败
        {
            bValidFile = FALSE;
            break;
        }
        //读取文件内容
        ReadFile(hFile, buffer, MAXREAD, &i, NULL);
        CloseHandle(hFile);
        //显示读取到的内容，i为读取文本到buffer中的字节总数
        hdc = BeginPaint(hwnd, &ps);
        SelectObject(hdc, GetStockObject(SYSTEM_FIXED_FONT));
        SetTextColor(hdc, GetSysColor(COLOR_BTNTEXT));
        SetBkColor(hdc, GetSysColor(COLOR_BTNFACE));
        //假定是ASCII字符的文件
        DrawTextA(hdc, buffer, i, &rect, DTFLAG);

        EndPaint(hwnd, &ps);
        return 0;

    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    }
    return DefWindowProc(hwnd, message, wParam, lParam);
}
LRESULT CALLBACK ListProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    if (message == WM_KEYDOWN && wParam == VK_RETURN)
    {
        SendMessage(GetParent(hwnd), WM_COMMAND, MAKELONG(ID_LIST, LBN_DBLCLK), (LPARAM)hwnd);
    }
    return CallWindowProc(OldList, hwnd, message, wParam, lParam);
}