wxWidgets中wxString各类型转换

• http://www.cnzui.com/archives/290
  
• 1. 文本
• 2. char* 转 wxString
• 3. wxString 转 char*
• 4. wchar_t* 转 wxString
• 5. wxString 转 wchar_t*
• 6. wxString 转 TCHAR
• 7. int 转 wxString
• 8. float 转 wxString
• 9. wxString 转 integer number
• 10. wxString 转 floating-point number
• 11. std::string 转 wxString
• 12. wxString 转 std::string
• 13. std::wstring 转 wxString
• 14, wxString 转 std::wstring

   附加（数据库ADO类型）：

• 15. wxString 转 _bstr_t
• 16. _bstr_ 转 wxString
• 17. wxString 转 _variant_t
• 18. wxString 转 _variant_t

文本

A literal is a string written in code with "quotes around it". A literal is not a wxString, and (in wxWidgets 2.8) will not be implicitly converted to one. This means that you can never pass in a raw literal into a wxWidget function or method (unless you don't care about your app not building with Unicode-enabled wxWidgets builds)
文本是一个在代码中被引号包围的串，文本它不是一个单纯的wxString类型，并且(在wxWidgets 2.8中)不能被隐含的转换为一个wxString类型。这意味着你不能试图将光秃秃的将一段文本放到wxWidget函数或方法中通过编译(除非你不在意你的应用程序是需要在Unicode编码环境中通过编译的)。

MessageBox("I'm a mistake!")  // WRONG in WxWidgets 2.8 (OK in 2.9) 

Instead, wxWidgets (prior to wxWidgets 2.9) requires you to use one of these macros to turn literals into wxString-compatible characters:

_("text that can be translated")
wxT("text that won't be translated")
_T("same as wxT")
 
char* c = "sometext";
wxT(c) // WRONG, not a literal 

Rather than being a nuisance, the _(), wxT(), and _T() macros take care of some unicode issues and help with internationalization.

char* to wxString

const char* chars = "Hello world";
// assuming your string is encoded as UTF-8, change the wxConv* parameter as needed
wxString mystring(chars, wxConvUTF8);

wxString to char*

void my_function(const char* foo)
{
}
...
wxString mystring(wxT("HelloWorld"));
// you could give the encoding you want as a parameter to mb_str(), e.g. mb_str(wxConvUTF8)
my_function( mystring.mb_str() );

mb_str() 返回一个临时的指针，如果你需要通过函数得到更多的返回结果(就和上面的情况一样)，你可以临时保存一下这个字符数据流：

wxString s( wxT("some string") );
wxCharBuffer buffer=s.ToUTF8();
foo( buffer.data() );  // data() returns const char *
bar( buffer.data(), strlen(buffer.data()) );  // in case you need the length of the data 

当你真的需要将它复制为char*类型时：

wxString mystring(wxT("HelloWorld"));
char cstring[1024];
// assuming you want UTF-8, change the wxConv* parameter as needed
strncpy(cstring, (const char*)mystring.mb_str(wxConvUTF8), 1023);

你也可以用ToUTF8(), 因为你得到的编码比用mb_str()函数从const char*转换成char*更加清楚。

wxString mystring(wxT("HelloWorld"));
(const_cast((const char*)mystring.mb_str()))

在可变参数的函数 (如printf)中用mb_str()函数将无效，但按以下的方法是有效的：

wxString mystring(wxT("HelloWorld"));
printf("%s",mystring.mb_str().data());

做为选择，使用Potential Unicode Pitfalls中推荐的方法：

printf("%s", (const char*)mystring.mb_str())

wchar_t* to wxString

const wchar_t* chars = L"Hello world";
wxString mystring(chars);

wxString to wchar_t*

请翻阅官方文档的以下方法：

wxString::wc_str()
wxString::wchar_str()

 

wxString to TCHAR

TCHAR tCharString[255];
wxString myString(_T("Hello World"));
const wxChar* myStringChars = myString.c_str();
for (int i = 0; i < myString.Len(); i++) {
   tCharString[i] = myStringChars [i];
}
tCharString[myString.Len()] = _T('\0');

int to wxString

wxString mystring = wxString::Format(wxT("%i"),myint);

或者

wxString mystring;
mystring << myint;

float to wxString

wxString mystring = wxString::Format(wxT("%f"), myfloat);

或者

wxString mystring;
mystring << myfloat;

wxString to integer number

wxString number(wxT("145"));
long value;
if(!number.ToLong(&value)) { /* error! */ }

或者

wxString str = _T("123");
int num;
 
num = wxAtoi(str);

wxString to floating-point number

wxString number(wxT("3.14159"));
double value;
if(!number.ToDouble(&value)){ /* error! */ }

std::string to wxString

std::string stlstring = "Hello world";
// assuming your string is encoded as UTF-8, change the wxConv* parameter as needed
wxString mystring(stlstring.c_str(), wxConvUTF8);

从wxWidgets 2.9开始, 你可以用适当的构造函数：

std::string stlstring = "Hello world";
// assuming your string is encoded as the current locale encoding (wxConvLibc)
wxString mystring(stlstring);

wxString to std::string

在wxWidgets 2.8 :

wxString mystring(wxT("HelloWorld"));
std::string stlstring = std::string(mystring.mb_str());

在wxWidgets 2.9, 你可以用这个方法

wxString::ToStdString()

std::wstring to wxString

从wxWidgets 2.9开始, 你可以用适当的构造函数：

std::sstring stlstring = L"Hello world";
// assuming your string is encoded as the current locale encoding (wxConvLibc)
wxString mystring(stlstring);

wxString to std::wstring

在wxWidgets 2.9, 你可以用这个方法

wxString::ToStdWstring()

附：（数据库类型）

wxString 转 _bstr_t
 

wxString str(wxT("Hello"));
_bstr_t mystring=_bstr_t(str.wc_str());

_bstr_ 转 wxString

_bstr_t bstr="hello";
wxString mystring = wxString(static_cast<const wchar_t *>(bstr));

_variant_t 转 wxString

_variant_t  varstr=_variant_t("Hello");
wxString mystring=wxString(static_cast<const wchar_t *>(_bstr_t(varstr)));

wxString 转 _variant_t

wxString str(wxT("Hello"));
_variant_t myvar=_variant_t(str.wc_str());

 

本文翻译自wxWidgets官方：http://wiki.wxwidgets.org/Converting_everything_to_and_from_wxString

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