如何将cli ::数组从本地代码转换为本机数组？ [英] How do I convert a cli::array to a native array from native code?

问题描述

我在用C ++ \CLI编写的托管组件周围编写一个本地包装器。

I'm writing a native wrapper around a managed component written in C++\CLI.

我在托管代码中有以下函数：

I have the following function in managed code:

array<Byte>^ Class::Function();

我想使用以下签名从本地C ++类公开此函数：

I want to expose this function from a native C++ class with the following signature:

shared_array<unsigned char> Class::Function();

我已经从本地代码调用管理函数，但我不确定如何安全地将受管阵列复制到非托管阵列中。

I've gotten as far as calling the managed function from native code, but I'm not sure how to safely copy the managed array into an unmanaged one.

gcroot<cli::array<System::Byte>^> managedArray = _managedObject->Function();

推荐答案

有两种常用方法：

1. 使用本机代码执行封送处理，这需要使用 pin_ptr<> ：

boost::shared_array<unsigned char> convert(array<unsigned char>^ arr)
{
    boost::shared_array<unsigned char> dest(new unsigned char[arr->Length]);
    pin_ptr<unsigned char> pinned = &arr[0];
    unsigned char* src = pinned;
    std::copy(src, src + arr->Length, dest.get());
    return dest;
}

使用托管代码执行封送处理， a href =http://msdn.microsoft.com/en-us/library/system.runtime.interopservices.marshal.aspx =nofollow> Marshal 类：

boost::shared_array<unsigned char> convert(array<unsigned char>^ arr)
{
    using System::Runtime::InteropServices::Marshal;

    boost::shared_array<unsigned char> dest(new unsigned char[arr->Length]);
    Marshal::Copy(arr, 0, IntPtr(dest.get()), arr->Length);
    return dest;
}

后者的方法，因为前者可以阻碍GC的有效性，如果数组很大。

Generally I would prefer the latter approach, as the former can hinder the GC's effectiveness if the array is large.

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