在OpenCV中使用Win32 OpenFile对话框出现问题 [英] Trouble using Win32 OpenFile dialog box in OpenCV

问题描述

亲爱的同事，

我试图使用对话框来选择要在OpenCV中使用的AVI文件的文件名. OpenCV函数称为:cvCaptureFromAVI.要创建打开文件"对话框，我正在使用Windows函数:
GetOpenFileName

我怀疑我遇到的麻烦与整个项目都是用Unicode编写的事实有关，并且OpenCV函数期望使用const char *.如果我将AVI文件名硬编码为char *变量，而我没有打开对话框，则一切似乎都可以正常工作.但是，当我尝试使用该对话框时，cvCaptureFromAVI函数将不起作用.换句话说，即使我不使用对话框中存储的文件名，也仍然无法使用AVI文件.仅仅打开对话框本身似乎就搞砸了.

这是有效的方法:

Dear Colleagues,

I''m attempting to use a dialog box to select the filename of an AVI file that I want to use in OpenCV. The OpenCV function is called: cvCaptureFromAVI. To create the Open File dialog box, I am using the Windows function:
GetOpenFileName

I suspect that the trouble I am having has something to do with the fact that my whole project is written in Unicode, and the OpenCV function expects const char*. If I hard-code the AVI filename as a char* variable, and I don''t open the dialog box, everything seems to work. However, as soon as I try to use the dialog box, the cvCaptureFromAVI function won''t work. In other words, even if I don''t use the filename stored from the dialog box, I still won''t be able to use my AVI file. Just opening the dialog box itself seems to screw it up.

Here is what works:

char filename[40] = "C:\\Users\\weylspinor\\Desktop\\test.avi";
CvCapture *G_movie_file = cvCaptureFromAVI(filename);

现在，如果我添加以下内容，它将不起作用. (请注意，我什至没有使用存储在OPENFILENAME结构中的文件名):

Now if I add the following, it doesnt work. (Note, I''m not even using the filename stored in the OPENFILENAME structure):

OPENFILENAME ofn;       // common dialog box structure
char szFile[260] = "";       // buffer for file name
HANDLE hf;              // file handle

// Initialize OPENFILENAME
ZeroMemory(&ofn, sizeof(ofn));
ofn.lStructSize = sizeof(ofn);
ofn.hwndOwner   = h_main;
ofn.lpstrFile   = LPWSTR(szFile);

// Set lpstrFile[0] to '\0' so that GetOpenFileName does not
// use the contents of szFile to initialize itself.
ofn.lpstrFile       = LPWSTR(szFile);
ofn.nMaxFile        = sizeof(szFile);
ofn.lpstrFilter     = TEXT("Text Files (*.txt)\0*.txt\0All Files (*.*)\0*.*\0");
ofn.nFilterIndex    = 1;
ofn.lpstrFileTitle  = NULL;
ofn.nMaxFileTitle   = 0;
ofn.lpstrInitialDir = NULL;
ofn.Flags           = OFN_PATHMUSTEXIST | OFN_FILEMUSTEXIST;


// Display the Open dialog box.
if (GetOpenFileName(&ofn) == TRUE) {
    hf = CreateFile(ofn.lpstrFile,
        GENERIC_READ,
        0,
        (LPSECURITY_ATTRIBUTES) NULL,
        OPEN_EXISTING,
        FILE_ATTRIBUTE_NORMAL,
        (HANDLE) NULL);
}

char filename[40] = "C:\\Users\\weylspinor\\Desktop\\test.avi";
CvCapture *G_movie_file = cvCaptureFromAVI(filename);

我可以通过仅注释掉GetOpenFileName函数来使其重新工作.

I can get it to work again by just commenting out the GetOpenFileName function.

OPENFILENAME ofn;       // common dialog box structure
char szFile[260] = "";       // buffer for file name
HANDLE hf;              // file handle

// Initialize OPENFILENAME
ZeroMemory(&ofn, sizeof(ofn));
ofn.lStructSize = sizeof(ofn);
ofn.hwndOwner   = h_main;
ofn.lpstrFile   = LPWSTR(szFile);

// Set lpstrFile[0] to '\0' so that GetOpenFileName does not
// use the contents of szFile to initialize itself.
ofn.lpstrFile       = LPWSTR(szFile);
ofn.nMaxFile        = sizeof(szFile);
ofn.lpstrFilter     = TEXT("Text Files (*.txt)\0*.txt\0All Files (*.*)\0*.*\0");
ofn.nFilterIndex    = 1;
ofn.lpstrFileTitle  = NULL;
ofn.nMaxFileTitle   = 0;
ofn.lpstrInitialDir = NULL;
ofn.Flags           = OFN_PATHMUSTEXIST | OFN_FILEMUSTEXIST;


// Display the Open dialog box.
/*if (GetOpenFileName(&ofn) == TRUE) {
    hf = CreateFile(ofn.lpstrFile,
        GENERIC_READ,
        0,
        (LPSECURITY_ATTRIBUTES) NULL,
        OPEN_EXISTING,
        FILE_ATTRIBUTE_NORMAL,
        (HANDLE) NULL);
}*/

char filename[40] = "C:\\Users\\weylspinor\\Desktop\\test.avi";
CvCapture *G_movie_file = cvCaptureFromAVI(filename);

如果有人可以指出我的错误，我将不胜感激.

干杯，
-J

I''d appreciate it if anyone can point me to my error.

Cheers,
-J

推荐答案

您需要通过

You need to convert the returned filename from Unicode to Ansi via one of the wcstomb()[^] converters.

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