wxStringと各種データ型間の変換(wiki.wxwidgets.orgより抜粋)

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() returns a temporary pointer; if you need the output for more than one function call (as is the case above), you can store the char buffer for a little while :

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 

And if you really need to copy it in to char* (but why would you? ;) :

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);

You can also use ToUTF8(), since which encoding you get is clearer than with mb_str()
From const char* to char*:

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

Variadic functions (like printf) won't work with mb_str(), but this will work:

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

Alternatively, use the method recommended in Potential Unicode Pitfalls:

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*

See the following methods in the docs :

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);

or

wxString mystring;
mystring << myint;

float to wxString

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

or

wxString mystring;
mystring << myfloat;

wxString to integer number

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

or

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);

Starting from wxWidgets 2.9, you may also use the appropriate constructor

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

wxString to std::string

wxWidgets 2.8 :

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

Under wxWidgets 2.9, you may use

wxString::ToStdString()

std::wstring to wxString

Starting from wxWidgets 2.9, you may use the appropriate constructor

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

wxString to std::wstring

Under wxWidgets 2.9, you may use

wxString::ToStdWstring()