win api get selected file type

To get the selected file type using the WinAPI in Windows, you can use the following steps:

1. Obtain the handle to the open file dialog box using the GetOpenFileName or GetSaveFileName function.

2. Use the OFN_EXPLORER flag when calling GetOpenFileName or GetSaveFileName to indicate that the dialog box should use the newer Explorer-style interface.

3. Retrieve the selected file name using the lpstrFile member of the OPENFILENAME structure.

4. Determine the file extension by searching for the last occurrence of the '.' character in the file name.

5. Use the file extension to determine the file type by comparing it to a list of known file extensions and their corresponding file types.

Here is some sample code that demonstrates these steps:

OPENFILENAME ofn;
char szFile[MAX_PATH];

ZeroMemory(&ofn, sizeof(ofn));
ofn.lStructSize = sizeof(ofn);
ofn.hwndOwner = hwnd;
ofn.lpstrFile = szFile;
ofn.nMaxFile = sizeof(szFile);
ofn.Flags = OFN_EXPLORER | OFN_FILEMUSTEXIST;

if (GetOpenFileName(&ofn))
{
    char* ext = strrchr(szFile, '.');
    if (ext != NULL)
    {
        if (_stricmp(ext, ".txt") == 0)
        {
            // File is a text file
        }
        else if (_stricmp(ext, ".jpg") == 0 || _stricmp(ext, ".jpeg") == 0)
        {
            // File is a JPEG image
        }
        else if (_stricmp(ext, ".pdf") == 0)
        {
            // File is a PDF document
        }
        else
        {
            // File type is unknown
        }
    }
}
``