结构类型的固定大小数组

问题描述

我如何申报在C＃中的结构类型的固定大小的数组：

how do I declare fixed-size array of a structure type in C# :

[StructLayout(LayoutKind.Sequential,Pack=1), Serializable]
public unsafe struct MyStruct{
    ...
}

public class MyClass {
    ...
    public fixed MyStruct myStruct[256];
}

这将导致到CS1663：？结构类型的固定大小的缓冲区是不允许的，我怎么解决这个，我preFER不使用C＃或托管集合数据结构式的，因为我需要经常马歇尔这对本地C ++

this will result to CS1663 : fixed size buffers of struct type is not allowed, how do I workaround this ?, I prefer not to use C# or "Managed Collection data structure" type, as I need to frequently marshall this to native C++

推荐答案

如果你的C＃结构只使用基本的数据类型，并具有完全相同的布局在C ++中本机结构相同，让您可以与手动内存管理，这些限制不安全code。作为奖励，你将避免编组来提高性能。

If your C# struct uses only primitive data types and has exactly the same layout as your native struct in C++, you can get around these restrictions with manual memory management and unsafe code. As a bonus, you will improve performance by avoiding marshalling.

分配内存：

IntPtr arr = Marshal.AllocHGlobal (sizeof (MyStruct) * 256);

这是基本的malloc ，所以分配的内存是GC的意识之外。

This is basically malloc, so the allocated memory is outside the awareness of the GC.

您可以通过IntPtr的天然code，好像它是一个 MYSTRUCT [256] ，只有IntPtr的将被整理，而不是它所指向的内存。本机和托管code可以直接访问相同的内存。

You can pass the IntPtr to native code as if it were a MyStruct[256] and only the IntPtr will be marshalled, not the memory it points to. Native and managed code can access the same memory directly.

要读/写的结构与C＃中的数组中，使用C＃指针：

To read/write the structs in the array with C#, use C# pointers:

static unsafe MyStruct GetMyStructAtIndex (IntPtr arr, int index)
{
    MyStruct *ptr = ((MyStruct *)arr) + index;
    return *ptr;
}

static unsafe void SetMyStructAtIndex (IntPtr arr, int index, MyStruct value)
{
    MyStruct *ptr = ((MyStruct *)arr) + index;
    *ptr = value;
}

不要忘了

Marshal.FreeHGlobal (arr);

当你与内存中完成，以免费了。

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