元素在C＃字节数组和C ++字节数组之间 [英] Marshal between C# byte array and C++ byte array

问题描述

我有一个C＃数组< System :: Byte> ，我想把它转换为C ++ byte * 。我该怎么办？我使用C ++ / CLR，因为它允许我在同一个项目中使用托管/非托管代码。我基本上写一个DLL和一些方法，可以通过C＃调用，但包含非托管C ++代码。

I have a C# array<System::Byte> and I want that to translate to a C++ byte*. How can I do that? I am using C++/CLR because it lets me use managed/unmanaged code in the same project. I'm basically writing a DLL and making a few methods that can be called via C#, but that contain unmanaged C++ code.

基本上，我的C ++ / CLR方法头是这样的：

So basically, my C++/CLR method header is this:

void testMethod(array<Byte>^ bytesFromCSharp);

和 testMethod 将 bytesFromCSharp 转换为可以由其他非托管C ++代码使用的字节* 。我修改了 byte * 数组，并写了一个for循环逐个字节复制，但感觉就像应该有一个更好的解决方案。

and inside of that testMethod I would like to translate the bytesFromCSharp into a byte* which can be used by other unmanaged C++ code. I malloced the byte* array and wrote a for loop to copy byte by byte but it feels like there should be a better solution.

编辑：他的技巧范例从他的回答如下：

//C#
byte[] myBytes = {1,2,3,4};

//C++/CLI
void testMethod(array<byte>^ myBytes) {
    pin_ptr<byte> thePtr = &myBytes[0];
    byte* bPtr = thePtr;
    nativeCode(bPtr);
    ...
}

推荐答案

使用 pin_ptr<>模板类固定数组并生成本机代码可以使用的指针。固定它确保在本地代码使用它时，垃圾收集器不能移动数组。

Use the pin_ptr<> template class to pin the array and generate a pointer that native code can use. Pinning it ensures that the array cannot be moved by the garbage collector while the native code is using it.

只要确保本地代码不能使用数组后pin_ptr<>变量超出范围。这也意味着本地代码存储指针供以后使用不是好。如果是的话，您 有权复印。

Just make sure that the native code cannot use the array anymore after the pin_ptr<> variable goes out of scope. Which also means that native code storing the pointer for later use is not okay. If it does then you have to make a copy.

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