如何打开系统::字符串^成标准::字符串？ [英] How to turn System::String^ into std::string?

问题描述

所以，我的工作在CLR，创建在Visual C ++ .NET的DLL。

So i work in clr, creating .net dll in visual c++.

我超铀等code：

 static bool InitFile(System::String^ fileName, System::String^ container)
{
    return enc.InitFile(std::string(fileName), std::string(container));
}

有恩codeR是normaly resives的std ::字符串。但这里的编译器（Visual Studio中）给了我，如果我脱光了自std :: string的和C2440这是一般相同的参数C2664错误。 VS告诉我，它只是不能到系统::字符串^转换成标准::字符串。

having encoder that normaly resives std::string. but here the compiler (visual studio) gives me C2664 error if I strip out arguments from std::string and C2440 which is in general the same. VS tells me that it just can not to convert System::String^ into std::string.

所以，我很伤心......我应该怎么做才能把系统::字符串^成标准::字符串？

So I am sad... what shall I do to turn System::String^ into std::string?

更新：

现在你的帮助，我有这样的code

Now with your help I have such code

#include <msclr\marshal.h>
#include <stdlib.h>
#include <string.h>
using namespace msclr::interop;
namespace NSSTW
{
  public ref class CFEW
  {
 public:
     CFEW() {}

     static System::String^ echo(System::String^ stringToReturn)
    {
        return stringToReturn;  
    }

     static bool InitFile(System::String^ fileName, System::String^ container)
    {   
        std::string sys_fileName = marshal_as<std::string>(fileName);;
        std::string sys_container = marshal_as<std::string>(container);;
        return enc.InitFile(sys_fileName, sys_container);
    }
...

但是当我尝试编译它给了我C4996

but when I try to compile it gives me C4996

错误C4996：msclr ::互操作:: error_reporting_helper＆LT; _To_Type，_From_Type> :: marshal_as：这种转换是不支持的图书馆或需要这种转换头文件不包括在内。请参考上的文档如何：扩展编组库添加你自己的封法

error C4996: 'msclr::interop::error_reporting_helper<_To_Type,_From_Type>::marshal_as': This conversion is not supported by the library or the header file needed for this conversion is not included. Please refer to the documentation on 'How to: Extend the Marshaling Library' for adding your own marshaling method.

该怎么办？

推荐答案

如果您使用的是VS2008或更新，您可以使用的自动编组加入到C ++ 。例如，您可以从转换系统::字符串^ 到的std ::字符串通过的 marshal_as ：

If you're using VS2008 or newer, you can do this very simply with the automatic marshaling added to C++. For example, you can convert from System::String^ to std::string via marshal_as:

System::String^ clrString = "CLR string";
std::string stdString = marshal_as<std::string>(clrString);

这是用于P中的同一个编组/ Invoke的调用。

This is the same marshaling used for P/Invoke calls.

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