6  

short answer you can't marshal variable length array as an array , because Without knowing the size, the interop marshalling service cannot marshal the array elements

简短的回答你不能编组可变长度数组作为数组,因为不知道大小,互操作编组服务不能编组数组元素

but if you know the size it will be like below:

但如果您知道尺寸,它将如下所示:

int arr[15]

you will be able to marshal it like this:

你将能够像这样编组它:

[MarshalAs(UnmanagedType.LPArray, SizeConst=15)] int[] arr

if you don't know the length of the array and this is what you want you can convert it to intprt and deal with inptr but first you need to create 2 structs

如果你不知道数组的长度这是你想要的,你可以将它转换为intprt并处理inptr但首先你需要创建2个结构

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi, Pack = 1)]
struct fvec_t1
{
    public uint whatever;

    public int[] data;
}

the other one like below:

另一个如下:

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi, Pack = 1)]
struct fvec_t2{
    public uint whatever;
}

create a function to initialize the array like below

创建一个函数来初始化数组,如下所示

private static int[] ReturnIntArray()
{
    int [] myInt = new int[30];

    for (int i = 0; i < myInt.length; i++)
    {
        myInt[i] = i + 1;
    }

    return myInt;
}

instantiate the first struct

实例化第一个结构

fvec_t1 instance = new fvec_t1();
instance.whatever=10;
instance.data= ReturnIntArray();

instantiate the second struct

实例化第二个结构

fvec_t2 instance1 = new fvec_t2();

instance1.whatever = instance.whatever

dynamically allocate space for fvec_t2 struct with extended space for data array

为数据数组的扩展空间动态分配fvec_t2结构的空间

IntPtr ptr = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(fvec_t2)) + Instance.data.Length);

Transfer the existing field values of fvec_t2 to memory space pointed to by ptr

将fvec_t2的现有字段值传输到ptr指向的内存空间

Marshal.StructureToPtr(instance1, ptr, true);

Calculate the offset of data array field which should be at the end of an fvec_t2 struct

计算应该位于fvec_t2结构末尾的数据数组字段的偏移量

int offset = Marshal.SizeOf(typeof(fvec_t2));

get memory address of data array field based on the offset.

根据偏移量获取数据阵列字段的内存地址。

IntPtr address = new IntPtr(ptr.ToInt32() + offset);

copy data to ptr

将数据复制到ptr

Marshal.Copy(instance.data, 0, address, instance.data.Length);

do the call

打电话

bool success = dllfunction(ptr);

Marshal.FreeHGlobal(ptr);
ptr = IntPtr.Zero;

-1  

In the above case I'd definitely use the SizeParamIndex.

在上面的例子中,我肯定会使用SizeParamIndex。

[StructLayout(LayoutKind.Sequential)]
public struct fvec_t1
{
    uint length;
    [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 0)] float[] data;
}

Good luck.