Convert from wxString to std::string

Convert from wxString to std::string
Posted on 2008-11-15 09:49 chefZ 阅读(182) 评论(0) 编辑 收藏 引用
http://wiki.wxwidgets.org/Converting_ev ... m_wxString

http://wiki.wxwidgets.org/WxString

Converting everything to and from wxString
From WxWiki
Jump to: navigation, search

This question seems common so I thought I'd write an article. Note that sometimes there may be more than one possible solutions, so don't forget to check the docs.

Note that it is recommended to use wxString as much as possible. Do no use char* or std::string unless you use a third-party library that requires you to do so.
Contents
[hide]

* 1 Literals
* 2 char* to wxString
* 3 wxString to char*
* 4 int to wxString
* 5 float to wxString
* 6 wxString to integer number
* 7 wxString to floating-point number
* 8 std::string to wxString
* 9 wxString to std::string

[edit] Literals

A literal is a string written in code with "quotes around it". A literal is not a wxString, and will not be implicitly converted to one. This means that you can never pass in a raw literal into a wxWidget function or method.

MessageBox("I'm a mistake!") // WRONG

Instead, Unicode builds (prior to wxWidgets 3) require you to use one of these macros to turn literals into wxStrings:

_("text that can be translated")
wxT("text that can'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.
[edit] char* to wxString

char* chars = "Hello world";
wxString mystring(chars, wxConvUTF8);

[edit] wxString to char*

void my_function(const char* foo)
{
}
...
wxString mystring(wxT("HelloWorld"));
my_function( mystring.mb_str() );

mb_str() returns a temporary pointer. If you need to store it in a char* :

wxString mystring(wxT("HelloWorld"));
char cstring[1024];
strcpy(cstring, (const char*)mystring.mb_str(wxConvUTF8));

[edit] int to wxString

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

or

wxString mystring;
mystring << myint;

[edit] float to wxString

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

or

wxString mystring;
mystring << myfloat;

[edit] wxString to integer number

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

[edit] wxString to floating-point number

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

[edit] std::string to wxString

std::string stlstring = "Hello world";
wxString mystring(stlstring.c_str(), wxConvUTF8);

[edit] wxString to std::string

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

wxWidgets 中的 C 字符串

wxWidgets 中的 C 字符串
关键字: wxwidgets, lua

在 wxWidgets 中处理 C 语言字符串真是一件令人头痛的事情，因为 wxWidgets 库是 C++ 编写的，类中的成员函数大多使用 wxChar*, wxString 作为参数。然而众所周知，在 C 语言里，字符串是以字符数组的形式存储，所以当 wxWidgets 需要和一些 C 库结合使用的时候，比如 Lua，难免会遇到将 C 字符串实例化成 wxString 或 wxChar* 对象的过程中出现乱码的问题。而且这种乱码的出现与一般编程中遇到的乱码不太一样，使用的转换方法不正确，不论是中文还是英文都会出现乱码，一视同仁。

一开始，我都是按照文档中的例子使用 wxString::Printf 方法进行转换，通常情况下不会有问题，例如：


C++代码

1. wxString temp;
2. temp.Printf(wxT("abc");//字符显示正确
3. temp.Printf(wxT("测试");//字符显示正确

wxString temp;
temp.Printf(wxT("abc");//字符显示正确
temp.Printf(wxT("测试");//字符显示正确




但是使用一段时间之后发现 Printf 函数只能正确得到第一个参数中的字符，其他参数中的字符都会变成乱码，即使是英文字符也会有问题，例如：


C++代码

1. wxString temp;
2. const char * str = "abc";
3. temp.Printf(wxT("%s", "abc");//temp会包含乱码
4. temp.Printf(wxT("%s", str);//temp会包含乱码

wxString temp;
const char * str = "abc";
temp.Printf(wxT("%s", "abc");//temp会包含乱码
temp.Printf(wxT("%s", str);//temp会包含乱码




阅读官方文档后，我发现 wxWidgets 还提供了另外一个函数 wxString::FromUTF8，函数声明如下：


C++代码

1. static wxString FromUTF8(const char* s)
2. static wxString FromUTF8(const char* s, size_t len)

static wxString FromUTF8(const char* s)
static wxString FromUTF8(const char* s, size_t len)




使用 wxString::FromUTF8 就可以顺利地解决问题，而且这还是一个静态函数，不需要实例化就可以调用，函数执行成功会返回 wxString 的一个实例：


C++代码

1. const char * str = "abc";
2. wxString::FromUTF8("abc");//返回 wxString 实例，值为"abc"
3. wxString::FromUTF8(str);//返回值与上一条语句相同

const char * str = "abc";
wxString::FromUTF8("abc");//返回 wxString 实例，值为"abc"
wxString::FromUTF8(str);//返回值与上一条语句相同




如果遇到要将 wxString 转化成为 char* 的情况，有三个函数可供使用：wxString::c_str(), wxString::wc_str(), wxString::mb_str()

mb_str returns a C string representation of the string, a const char*, regardless of whether Unicode is enabled. In Unicode mode, the string is converted, and data may be lost.

wc_str returns a wide character representation of the string, a wchar_t*, regardless of whether Unicode is enabled. In ANSI mode, the string is converted to Unicode.

c_str returns a pointer to the string data (const char* in ANSI mode, const wchar_t* in Unicode mode). No conversion takes place.