How to get a char * arr[] from a managed array<String^>^?

Question

I'm a bit confused how to get a char * Bar[] of an array<String^>^.

My unmanaged function look's kinda this:

void NativeClass::Foo(char * Bar[])
{
    SomeAPIFunction(Bar);
}

Managed Part (should only give an idea of what i am trying to achieve):

void ManagedClass::Foo(array<String^>^ Bar)
{
    NativeClass * MyNativeClass = new NativeClass();
    MyNativeClass->Foo(Bar);
}

• Found pin_ptr. Can't get it to work.
• For String^ to char * i use this: char * NewFoo = (char*)(void*)Marshal::StringToHGlobalAnsi(Foo);. Maybe there is an opportunity to go in such a way?
• I can't change the SomeAPIFunction(Bar).
• The size of my managed Bar is not fixed.

Answer 1

There are utility methods to convert a single string for you, but for the array, you'll need to do it yourself.

This is what I would do: First, convert to C++ classes, because they're convenient and handle most of the memory allocation that you need to deal with. Then, create the char*[] to point at the C++ objects.

void ManagedClass::Foo(array<String^>^ managedArray)
{
    std::vector<std::string> vec;
    for each (String^ managedStr in managedArray)
        vec.push_back(marshal_as<std::string>(managedStr));

    char** unmanagedArray = new char*[vec.size()];
    for (size_t i = 0; i < vec.size(); i++)
        unmanagedArray[i] = vec[i].c_str();

    NativeClass * MyNativeClass = new NativeClass();
    MyNativeClass->Foo(unmanagedArray);

    delete[] unmanagedArray;
}

_{Disclaimer: I'm not at a compiler at the moment, there may be minor syntax errors.}