'CreateFileW' : cannot convert parameter 1 from 'const char [13]' to 'LPCWSTR'

'CreateFileW' : cannot convert parameter 1 from 'const char [13]' to 'LPCWSTR' – VBForums

In this article the author writes:

You have three valid options. All others are invalid. The third of these options is the best.
Option 1: Force ANSI (slower on NT, doesn't work on CE, possible problems with internationalization)

Code:

hFile = CreateFileA("C:\\tab.doc",GENERIC_READ|GENERIC_WRITE,
 FILE_SHARE_READ,NULL,OPEN_ALWAYS,FILE_ATTRIBUTE_NORMAL,NULL);

Option 2: Force Unicode (doesn't work on 9x)

Code:

hFile = CreateFileW(L"C:\\tab.doc",GENERIC_READ|GENERIC_WRITE,
 FILE_SHARE_READ,NULL,OPEN_ALWAYS,FILE_ATTRIBUTE_NORMAL,NULL);

Option 3: Make it easily switchable in the project settings (easy to get working and ideal versions for everywhere)

Code:

hFile = CreateFile(TEXT("C:\\tab.doc"),GENERIC_READ|GENERIC_WRITE,
 FILE_SHARE_READ,NULL,OPEN_ALWAYS,FILE_ATTRIBUTE_NORMAL,NULL);

If you include <tchar.h>, you can use _TEXT() or _T() instead of TEXT(), but that is the only permitted variation. Everything else is invalid.

 

OTHER SAY:

Now go into the project settings and change using Unicode to multi-byte character set and see if it still compiles.

    其实主要的问题是vc2008 字符集的问题,其中默认的[字符集]为 “使用Unicode 字符集“,所以把他改为 “使用多字节字符集”就可以了。

    设置:单栏里,点“项目”,然后选“属性”(最后一项),再点“配置属性”,是个“+”号,把它展开,然后选“常规”选项卡,倒数第三项“字符集”,选择你想用的吧。

  网上有人的建议:

不过还是建议使用Unicode,否则你的程序将有很大的局限性;
要是你的程序只在西方发布还好,但毕竟是适应中国大陆的程序吧,所以建议使用Unicode。
LPSTR LPCSTR LPWSTR LPCWSTR区别 

LPSTR 一个32位的指向字符串的指针
LPCSTR 一个32位的指向字符串常量的指针
LPWSTR 一个32位的指向unicode字符串的指针
LPCWSTR 一个32位的指向unicode字符串常量的指针
前面的L代表LONG,P就是指针的意思,C就是constant的意思
W是wide的意思,STR就是string的意思

LPSTR = char *
LPCSTR = const char *
LPWSTR = wchar_t *
LPCWSTR = const wchar_t *
LPOLESTR = OLECHAR * = BSTR = LPWSTR(Win32)
LPCOLESTR = const OLECHAR * = LPCWSTR(Win32)
LPTSTR = _TCHAR *
LPCTSTR = const _TCHAR *

多字节字符串与宽字符串的转换可使用C API者Win32 API.
C API: mbstowcs,wcstombs
Win32 API: MultiByteToWideChar, WideCharToMultiByte

下面着重介绍Win32 API的用法,C API的用法较为简单可参照Win32 API。

首先是WideCharToMultiByte

通常你需要配置4个参数(其他参数如是使用即可),红色标记的部分。
依次是源宽字符串,需要转换的长度(-1,则为转换整个字符串),目标多字节字符串,目标缓冲区长度。
返回值表示转换为目标多字节字符串实际需要的长度(包括结束符)。
所以通常需要调用WideCharToMultiByte两次:第一次产生目标缓冲区长度,第二次产生目标字符串,像下面这样
wchar_t* wcs = L"中国,你好!I Love You!";
int lengthOfMbs = WideCharToMultiByte( CP_ACP, 0, wcs, -1, NULL, 0, NULL, NULL);
char* mbs = new char[ lengthOfMbs ];
WideCharToMultiByte( CP_ACP, 0, wcs, -1, mbs, lengthOfMbs, NULL, NULL);   
delete mbs;
mbs = NULL;
MultiByteToWideChar的用法类似
char* mbs = "中国,你好!I Love You!";
int lengthOfWcs = MultiByteToWideChar( CP_ACP, 0, mbs, -1, NULL, 0 );
wchar_t* wcs = new wchar_t[ lengthOfWcs ];
MultiByteToWideChar( CP_ACP, 0, mbs, -1, wcs, lengthOfWcs );
delete wcs;
wcs = NULL;

下面两个函数封装了转换过程
#include <Windows.h>
#include <string>

std::string WcsToMbs( const std::wstring& wcs ) {   
    int lengthOfMbs = WideCharToMultiByte( CP_ACP, 0, wcs.c_str(), -1, NULL, 0, NULL, NULL);
    char* mbs = new char[ lengthOfMbs ];
    WideCharToMultiByte( CP_ACP, 0, wcs.c_str(), -1, mbs, lengthOfMbs, NULL, NULL);
    std::string result = mbs;
    delete mbs;
    mbs = NULL;
    return result;
}

std::wstring MbsToWcs( const std::string& mbs ) {   
    int lengthOfWcs = MultiByteToWideChar( CP_ACP, 0, mbs.c_str(), -1, NULL, 0 );
    wchar_t* wcs = new wchar_t[ lengthOfWcs ];
    MultiByteToWideChar( CP_ACP, 0, mbs.c_str(), -1, wcs, lengthOfWcs );
    std::wstring result = wcs;
    delete wcs;
    wcs = NULL;
    return result;

posted @ 2011-08-06 10:15  csqlwy  阅读(11955)  评论(1编辑  收藏  举报