你如何将 CString 和 std::string std::wstring 相互转换?

2022-01-12 00:00:00 c++ mfc stdstring c-strings

CString 非常方便，而 std::string 更兼容 STL 容器.我正在使用 hash_map.但是， hash_map 不支持 CString 作为键，所以我想将 CString 转换为 std::string.


CString is quite handy, while std::string is more compatible with STL container. I am using hash_map. However, hash_map does not support CStrings as keys, so I want to convert the CString into a std::string.
编写 CString 哈希函数似乎需要很多时间.

Writing a CString hash function seems to take a lot of time.
CString -----> std::string

我该怎么做?
std::string -----> CString:

inline CString toCString(std::string const& str)
{
    return CString(str.c_str()); 
}

我说的对吗?

这里有更多问题:
如何从 wstring 转换为 CString 以及反之亦然?

How can I convert from wstring to CString and vice versa?
// wstring -> CString
std::wstring src;
CString result(src.c_str());

// CString -> wstring
CString src;
std::wstring des(src.GetString());

这有什么问题吗?
另外，如何从 std::wstring 转换为 std::string 以及反之亦然?

Additionally, how can I convert from std::wstring to std::string and vice versa?
推荐答案
根据CodeGuru:
CString 到 std::string:
CString cs("Hello");
std::string s((LPCTSTR)cs);

BUT: std::string 不能总是从 LPCTSTR 构造.即，UNICODE 构建的代码将失败.

BUT: std::string cannot always construct from a LPCTSTR. i.e. the code will fail for UNICODE builds.
由于 std::string 只能从 LPSTR/LPCSTR 构造，使用 VC++ 7.x 或更高版本的程序员可以利用转换CT2CA 等类作为中介.

As std::string can construct only from LPSTR / LPCSTR, a programmer who uses VC++ 7.x or better can utilize conversion classes such as CT2CA as an intermediary.
CString cs ("Hello");
// Convert a TCHAR string to a LPCSTR
CT2CA pszConvertedAnsiString (cs);
// construct a std::string using the LPCSTR input
std::string strStd (pszConvertedAnsiString);

std::string 到 CString:(来自 Visual Studio 的 CString 常见问题解答...)
std::string s("Hello");
CString cs(s.c_str());

CStringT 可以从字符或宽字符串构造.即它可以从char*(即LPSTR)或wchar_t*(LPWSTR)转换.

CStringT can construct from both character or wide-character strings. i.e. It can convert from char* (i.e. LPSTR) or from wchar_t* (LPWSTR).
换句话说，char-specialization (of CStringT) ie CStringA, wchar_t-specilization CStringW,和 TCHAR-specialization CString 可以从 char 或宽字符构造，空终止(空终止在这里非常重要) 字符串来源.
Althoug IInspectable 修改了null-termination"部分 在评论中:

In other words, char-specialization (of CStringT) i.e. CStringA, wchar_t-specilization CStringW, and TCHAR-specialization CString can be constructed from either char or wide-character, null terminated (null-termination is very important here) string sources.

Althoug IInspectable amends the "null-termination" part in the comments:
不需要 NUL 终止.
CStringT 具有采用显式长度参数的转换构造函数.这也意味着您可以使用嵌入 NUL 字符的 std::string 对象构造 CStringT 对象.


  NUL-termination is not required.

  CStringT has conversion constructors that take an explicit length argument. This also means that you can construct CStringT objects from std::string objects with embedded NUL characters.


	
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