CODEWITHSUNDEEP
c++c++-cli
olidev
olidev

Reputation: 20644

sending a list of string from C# to C++ causes errors

I want to send a C# a list of string into C++ code using C++/CLI:

in C++, I put this in a constructor:

#include <string>

public:
  MyAlgorithm(array<std::string>^ listAlgorithms);

But I got this compilation error:

error C2691: 'std::string' : a managed array cannot have this element type

And in the implementation I have:

MyAlgorithm(array<std::string>^ listAlgorithms)
{
   pin_ptr<std::string> algorithms = &listAlgorithms[0];
   std::string* unmanagedAlgorithms = algorithms;
}

And I got this error:

error C2440: 'initializing' : cannot convert from 'cli::interior_ptr<Type>' to 'cli::pin_ptr<Type>'

How should I correct them?

Thanks in advance.

Upvotes: 0

Views: 1018

Answers (2)

Serj-Tm
Serj-Tm

Reputation: 16981

#include <string>

#include <msclr/marshal_cppstd.h>


MyAlgorithm(array<String^>^ listAlgorithms)
{
    std::vector<std::string> unmanagedAlgorithms(listAlgorithms->Length);
    for (int i = 0; i < listAlgorithms->Length; ++i)
    {
        auto s = listAlgorithms[i];
        unmanagedAlgorithms[i] = msclr::interop::marshal_as<std::string>(s);
    }

 }

or

    std::vector<std::string> unmanagedAlgorithms;
    for each (auto algorithm in listAlgorithms)
    {
        unmanagedAlgorithms.push_back(msclr::interop::marshal_as<std::string>(algorithm));
    }

or first string only

    String^ managedAlgorithm = listAlgorithms[0];
    std::string unmanagedAlgorithm = msclr::interop::marshal_as<std::string>(managedAlgorithm);

Upvotes: 2

blueberryfields
blueberryfields

Reputation: 50388

Y'all can't use classes when defining a managed array. If you're looking to use the std::string class, you're probably best going with something like std::vector.

PS: How come you don't do?

using namespace std;

Upvotes: 0

Related Questions