使用文件对话框获取路径

Question

我正在构建一个程序，要求一个文件，然后过滤到用户想要的(黑白，平滑等)。我在opencv中使用过滤器，windows.h用于GUI。但是要将图片加载到opencv中的Pimage中，我需要图像的完整路径。因此，我可以给用户文本框，并告诉他写所有的路径，但这将是非常讨厌的程序.

然后，我记得在Photoshop和他的漂亮的文件对话框，允许我加载文件，而不写所有的路径。

在google中快速搜索给我OPENFILENAME结构，但是当我尝试使用给我提供文件名称的函数时：

if(GetOpenFileName(&ofn))
    {
        printf("File path: %s", szFileName)
    }

它总是在控制台中给出以下错误：

undefined reference to `GetOpenFileNameA@4'
collect2: ld returned 1 exit status

糟透了！

总之，我只想要好的代码，我将按下“加载”按钮，文件对话框将打开，文件的完整路径将打印到屏幕上。到目前为止，这是我的代码(我和我的好朋友代码块)：

#if defined(UNICODE) && !defined(_UNICODE)
    #define _UNICODE
#elif defined(_UNICODE) && !defined(UNICODE)
    #define UNICODE
#endif

#include <tchar.h>
#include <windows.h>
#define HEIGHT 500
#define WIDTH 500
/*  Declare Windows procedure  */
LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);
HWND button_1;
/*  Make the class name into a global variable  */
TCHAR szClassName[ ] = _T("windows form");

int WINAPI WinMain (HINSTANCE hThisInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR lpszArgument,
                     int nCmdShow)
{
    HWND hwnd;               /* This is the handle for our window */
    MSG messages;            /* Here messages to the application are saved */
    WNDCLASSEX wincl;        /* Data structure for the windowclass */

    /* The Window structure */
    wincl.hInstance = hThisInstance;
    wincl.lpszClassName = szClassName;
    wincl.lpfnWndProc = WindowProcedure;      /* This function is called by windows */
    wincl.style = CS_DBLCLKS;                 /* Catch double-clicks */
    wincl.cbSize = sizeof (WNDCLASSEX);

    /* Use default icon and mouse-pointer */
    wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
    wincl.lpszMenuName = NULL;                 /* No menu */
    wincl.cbClsExtra = 0;                      /* No extra bytes after the window class */
    wincl.cbWndExtra = 0;                      /* structure or the window instance */
    /* Use Windows's default colour as the background of the window */
    wincl.hbrBackground = (HBRUSH) COLOR_BACKGROUND;

    /* Register the window class, and if it fails quit the program */
    if (!RegisterClassEx (&wincl))
        return 0;

    /* The class is registered, let's create the program*/
    hwnd = CreateWindowEx (
           0,                   /* Extended possibilites for variation */
           szClassName,         /* Classname */
           _T("windows form"),       /* Title Text */
           WS_OVERLAPPEDWINDOW, /* default window */
           CW_USEDEFAULT,       /* Windows decides the position */
           CW_USEDEFAULT,       /* where the window ends up on the screen */
           WIDTH,                 /* The programs width */
           HEIGHT,                 /* and height in pixels */
           HWND_DESKTOP,        /* The window is a child-window to desktop */
           NULL,                /* No menu */
           hThisInstance,       /* Program Instance handler */
           NULL                 /* No Window Creation data */
           );

    /* Make the window visible on the screen */
    ShowWindow (hwnd, nCmdShow);

    /* Run the message loop. It will run until GetMessage() returns 0 */
    while (GetMessage (&messages, NULL, 0, 0))
    {
        /* Translate virtual-key messages into character messages */
        TranslateMessage(&messages);
        /* Send message to WindowProcedure */
        DispatchMessage(&messages);
    }

    /* The program return-value is 0 - The value that PostQuitMessage() gave */
    return messages.wParam;
}


/*  This function is called by the Windows function DispatchMessage()  */

LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)                  /* handle the messages */
    {
        case WM_CREATE:
            button_1 = CreateWindow("BUTTON",
                "Open file", WS_VISIBLE | WS_CHILD | WS_BORDER,
                WIDTH/2, HEIGHT/2, 100, 40, hwnd, (HMENU) 1, NULL, NULL);
                break;
        case WM_DESTROY:
            PostQuitMessage (0);       /* send a WM_QUIT to the message queue */
            break;
        default:                      /* for messages that we don't deal with */
            return DefWindowProc (hwnd, message, wParam, lParam);
    }

    return 0;
}

Answer 1

如果不定义OPENFILENAME结构，就不能使用GetOpenFileName()。

LPSTR filebuff = new char[256];
OPENFILENAME open = { 0 };
            open.lStructSize = sizeof(OPENFILENAME);
            open.hwndOwner = window; //Handle to the parent window
            open.lpstrFilter = "Image Files(.jpg|.png|.bmp|.jpeg)\0*.jpg;*.png;*.bmp;*.jpeg\0\0";
            open.lpstrCustomFilter = NULL;
            open.lpstrFile = filebuff;
            open.lpstrFile[0] = '\0';
            open.nMaxFile = 256;
            open.nFilterIndex = 1;
            open.lpstrInitialDir = NULL;
            open.lpstrTitle = "Select An Image File\0";
            open.nMaxFileTitle = strlen("Select an image file\0");
            open.Flags = OFN_PATHMUSTEXIST | OFN_FILEMUSTEXIST | OFN_EXPLORER;

然后使用

if (GetOpenFileName(&open))
{
 printf("File name:%s", open.lpstrFile);
}

上面的代码选择一个图像文件，替换lpstrFilter值来筛选扩展、lpstrTitle和lpstrFilter。

这是OPENFILENAME结构文档

所有这些属性都是对话框显示所必需的！