C++/CLI从System :: String ^转换为std :: string

Question

有人可以发一个简单的代码,可以转换,

System::String^

至,

C++ std::string

即,我只想分配值,

String^ originalString;

至,

std::string newString;

Answer 1

不要自己滚动,使用Microsoft提供的这些方便(和可扩展)包装器.

例如:

#include <msclr\marshal_cppstd.h>

System::String^ managed = "test";
std::string unmanaged = msclr::interop::marshal_as<std::string>(managed);

Answer 2

退房System::Runtime::InteropServices::Marshal::StringToCoTaskMemUni()和它的朋友.

抱歉,现在无法发布代码; 在发布之前我没有VS在这台机器上检查它是否编译.

Answer 3

您可以轻松地执行以下操作

#include <msclr/marshal_cppstd.h>

System::String^ xyz="Hi boys"; 

std::string converted_xyz=msclr::interop::marshal_as< std::string >( xyz);

Answer 4

这对我有用:

#include <stdlib.h>
#include <string.h>
#include <msclr\marshal_cppstd.h>
//..
using namespace msclr::interop;
//..
System::String^ clrString = (TextoDeBoton);
std::string stdString = marshal_as<std::string>(clrString); //String^ to std
//System::String^ myString = marshal_as<System::String^>(MyBasicStirng); //std to String^
prueba.CopyInfo(stdString); //MyMethod
//..
//Where: String^ = TextoDeBoton;
//and stdString is a "normal" string;

Answer 5

以下是我多年前为c ++/cli项目编写的一些转换例程,它们应该仍然有用.

void StringToStlWString ( System::String const^ s, std::wstring& os)
    {
        String^ string = const_cast<String^>(s);
        const wchar_t* chars = reinterpret_cast<const wchar_t*>((Marshal::StringToHGlobalUni(string)).ToPointer());
        os = chars;
        Marshal::FreeHGlobal(IntPtr((void*)chars));

    }
    System::String^ StlWStringToString (std::wstring const& os) {
        String^ str = gcnew String(os.c_str());
        //String^ str = gcnew String("");
        return str;
    }

    System::String^ WPtrToString(wchar_t const* pData, int length) {
        if (length == 0) {
            //use null termination
            length = wcslen(pData);
            if (length == 0) {
                System::String^ ret = "";
                return ret;
            }
        }

        System::IntPtr bfr = System::IntPtr(const_cast<wchar_t*>(pData));
        System::String^ ret = System::Runtime::InteropServices::Marshal::PtrToStringUni(bfr, length);
        return ret;
    }

    void Utf8ToStlWString(char const* pUtfString, std::wstring& stlString) {
        //wchar_t* pString;
        MAKE_WIDEPTR_FROMUTF8(pString, pUtfString);
        stlString = pString;
    }

    void Utf8ToStlWStringN(char const* pUtfString, std::wstring& stlString, ULONG length) {
        //wchar_t* pString;
        MAKE_WIDEPTR_FROMUTF8N(pString, pUtfString, length);
        stlString = pString;
    }

Answer 6

我发现从String ^获取std :: string的简单方法是使用sprintf（）。

char cStr[50] = { 0 };
String^ clrString = "Hello";
if (clrString->Length < sizeof(cStr))
  sprintf(cStr, "%s", clrString);
std::string stlString(cStr);

无需调用元帅功能！

更新感谢Eric，我修改了示例代码以检查输入字符串的大小，以防止缓冲区溢出。

Answer 7

我花了好几个小时尝试将Windows窗体列表框ToString值转换为标准字符串,以便我可以将它与fstream一起输出到txt文件.我的Visual Studio没有附带编组头文件,我找到了几个使用的答案.经过这么多试验和错误,我终于找到了一个解决方案,解决了刚刚使用System :: Runtime :: InteropServices的问题:

void MarshalString ( String ^ s, string& os ) {
   using namespace Runtime::InteropServices;
   const char* chars = 
      (const char*)(Marshal::StringToHGlobalAnsi(s)).ToPointer();
   os = chars;
   Marshal::FreeHGlobal(IntPtr((void*)chars));
}

//this is the code to use the function:
scheduleBox->SetSelected(0,true);
string a = "test";
String ^ c = gcnew String(scheduleBox->SelectedItem->ToString());
MarshalString(c, a);
filestream << a;

这是MSDN页面的示例:http: //msdn.microsoft.com/en-us/library/1b4az623(v = vs.80).aspx

我知道这是一个非常简单的解决方案,但这需要我的故障排除和访问几个论坛,最终找到有用的东西.