C# Struct to delphi packed record

I have a function extracted from a delphi dll

function func_name(par1: Byte; par2: struct1) : boolean

Struct 1 is made up of :

struct1 = packed record
    Number: Byte;
    arrStr : array[1..8] of struct2;
end

Moreover struct2 is made up of:

struct2 = packed record
    Code: Byte;
    Price: Single;
end

Now using C# i am trying to pass a same time of structure to delphi using the following

First i created my structures:

[StructLayout(LayoutKind.Sequential, Pack = 1, CharSet = CharSet.Ansi)]
public struct struct2
{
    public byte code;
    public Single price;
}

[StructLayout(LayoutKind.Sequential, Pack = 1, CharSet = CharSet.Ansi)]
public struct struct1
{
    public byte Number;

    [MarshalAs(UnmanagedType.LPArray)]
    public struct2[] Prices;

    public struct1(int elements)
    {
        Number = 0;
        arrStr = new struct2[elements];
    }
}

Note elements is always 8.

So when i try to run the code thus filling the array and passing it to the function i get the following error:

Invalid managed/unmanaged type combination (Array fields must be paired with ByValArray or SafeArray)."

The array is inline in the struct. It is not a pointer. So instead of

[MarshalAs(UnmanagedType.LPArray)]

you must use

[MarshalAs(UnmanagedType.ByValArray, SizeConst = 8)]

C# Struct to delphi packed record

原文：https://www.cnblogs.com/cinemaparadiso/p/12159554.html