如何确定操作系统Windows XP后是否没有默认文件扩展名关联? [英] How to tell if there's no default file extension association on OS post-Windows XP?
问题描述
回到Windows XP的日子,可以使用以下代码来判断扩展程序是否存在文件关联:
Going back to the days of Windows XP one could use the following code to tell if there's no file association existed for an extension:
TCHAR buffPath[MAX_PATH] = {0};
DWORD dwszBuffPath = MAX_PATH;
HRESULT hR = ::AssocQueryString(
ASSOCF_NOFIXUPS | ASSOCF_VERIFY,
ASSOCSTR_EXECUTABLE,
_T(".weirdassextension"),
NULL,
buffPath,
&dwszBuffPath);
if(hR != S_OK &&
hR != E_POINTER)
{
//Association does not exist
}
但是从Windows 8开始, AssocQueryString
API返回 S_OK
和 buffPath
设置为类似于 C:\WINDOWS\ system32 \OpenWith。
But since Windows 8, the AssocQueryString
API returns S_OK
and buffPath
is set to something like C:\WINDOWS\system32\OpenWith.exe
if it doesn't find anything.
现在有更好的方法来确定文件扩展名没有Shell关联吗?
Is there a better way now to determine that file extension has no Shell association?
PS。我不想只是比较文件名到 OpenWith.exe
。
PS. I do not want to just compare the file name to OpenWith.exe
. What if there's a legit executable called just that... There must be a better way.
推荐答案
我想我得到了。诀窍是使用正确的标志。这似乎是从XP及以上工作:
I think I got it. The trick was to use the correct flags. This seems to work from XP and up:
WCHAR wbuffPath[MAX_PATH] = {0};
DWORD dwszBuffPath = MAX_PATH;
HRESULT hR = ::AssocQueryStringW(ASSOCF_INIT_IGNOREUNKNOWN,
ASSOCSTR_EXECUTABLE,
L".weirdassextension",
NULL,
wbuffPath,
&dwszBuffPath);
if(hR == 0x80070483) // HRESULT_FROM_WIN32(ERROR_NO_ASSOCIATION)
{
//The association is missing
}
有一个其他的骗局,花了我一些时间来解决 - 不要使用 AssocQueryStringA code>。
AssocQueryStringA()
的垫片,将其传递的字符串参数转换为Unicode在XP中有一个错误(和明显在Vista ) API在这些操作系统上失败。所以,如果你做你自己的ANSI到Unicode转换,并调用 AssocQueryStringW()
的问题将消失(显然,14年是没有足够的时间,微软修复该错误?)。
There's one other trick there, that took me some time to figure out -- DO NOT use AssocQueryStringA()
. The shim for AssocQueryStringA()
that converts its passed string parameters to Unicode has a bug in XP (and evidently in Vista as well) that will make that API fail on those OS. So, if you do your own ANSI-to-Unicode conversion and call AssocQueryStringW()
the problem will go away (Evidently 14 years is not enough time for Microsoft to fix that bug?).
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