将System :: array转换为std :: vector

Question

有没有人知道将CLI/.NET System ::数组转换为C++ std :: vector的简单方法,除了按元素方式进行操作外？

我正在CLI/C++中编写一个包装器方法(SetLowerBoundsWrapper,它接受System :: array作为参数),并将等效的std :: vector传递给本机C++方法(set_lower_bounds).目前我这样做如下:

using namespace System;

void SetLowerBoundsWrapper(array<double>^ lb)
{
    int n = lb->Length;
    std::vector<double> lower(n); //create a std::vector
    for(int i = 0; i<n ; i++)
    {
        lower[i] = lb[i];         //copy element-wise
    } 
    _opt->set_lower_bounds(lower);
}

Answer 1

另一种方法是让.NET BCL代替C++标准库来完成工作:

#include <vector>

void SetLowerBoundsWrapper(array<double>^ lb)
{
    using System::IntPtr;
    using System::Runtime::InteropServices::Marshal;

    std::vector<double> lower(lb->Length);
    Marshal::Copy(lb, 0, IntPtr(&lower[0]), lb->Length);
    _opt->set_lower_bounds(lower);
}

编辑(回应对Konrad答案的评论):

以下两者都使用VC++ 2010 SP1编译,并且完全等效:

#include <algorithm>
#include <vector>

void SetLowerBoundsWrapper(array<double>^ lb)
{
    std::vector<double> lower(lb->Length);
    {
        pin_ptr<double> pin(&lb[0]);
        double *first(pin), *last(pin + lb->Length);
        std::copy(first, last, lower.begin());
    }
    _opt->set_lower_bounds(lower);
}

void SetLowerBoundsWrapper2(array<double>^ lb)
{
    std::vector<double> lower(lb->Length);
    {
        pin_ptr<double> pin(&lb[0]);
        std::copy(
            static_cast<double*>(pin),
            static_cast<double*>(pin + lb->Length),
            lower.begin()
        );
    }
    _opt->set_lower_bounds(lower);
}

(人工范围是允许pin_ptr尽可能早地解锁内存,以免阻碍GC.)