如何使用 Marshal 转换字节数组中的结构

Question

I am trying to convert a structure into a byte array using Marshal. Below is my code snippet

    public struct DataFields
    {
        public byte return_code { get; set; }
        public byte sw_rev_major { get; set; }
        public byte sw_rev_minor { get; set; }
        public byte writelock_radio_state { get; set; }
        public byte protocol { get; set; }
        public byte dev_revision { get; set; }
        public byte mfg_id { get; set; }
        public byte dev_type { get; set; }
        public byte dev_function { get; set; }
        public byte[] dev_model { get; set; }
        public byte[] dev_tag { get; set; }

        public void InitDataFields()
        {
            this.return_code = 0x00;
            this.sw_rev_major = 0x01;
            this.sw_rev_minor = 0x00;
            this.writelock_radio_state = 0x20;
            this.protocol = 0x02;
            this.dev_revision = 0x01;
            this.mfg_id = 0x1f;
            this.dev_type = 0x4c;
            this.dev_function = 0x03;
            this.dev_model = new byte[] { 0x4d, 0x69, 0x63, 0x72, 0x6f, 0x20, 0x4d, 0x6f, 0x74, 0x69, 0x6f, 0x6e, 0x20, 0x34, 
                                          0x37, 0x30, 0x30, 0x00, 0x00, 0x00, 0x00,
                                          0x00, 0x00, 0x00, 0x00
                                        };

            this.dev_tag = new byte[] { 0x46, 0x54, 0x2d, 0x31, 0x30, 0x31, 0x00,
                                        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                                        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                                        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                                        0x00, 0x00, 0x00, 0x00
                                       };
        }

    }

    public static byte[] StructureToByteArray(DataFields str)
    {
        //Console.WriteLine($"parameter: {str}");
        int size = Marshal.SizeOf(str);
        //int size = 66;
        Console.WriteLine($"marshal size: {size}");
        byte[] arr = new byte[size];

        IntPtr ptr = Marshal.AllocHGlobal(size);
        Marshal.StructureToPtr(str, ptr, false);
        Marshal.Copy(ptr, arr, 0, size);
        //Marshal.DestroyStructure(ptr, typeof(T));
        return arr;
    }

When i am executing my code, StructureToByteArray() function is corrupting the values of dev_model and dev_tag. Can someone please help to find out whats going wrong here?

Answer 1

This is only a guess, as i am not sure what layout you actually want

[StructLayout(LayoutKind.Sequential)]
public struct DataFields
{
     public byte return_code;
     public byte sw_rev_major;
     public byte sw_rev_minor;
     public byte writelock_radio_state;
     public byte protocol;
     public byte dev_revision;
     public byte mfg_id;
     public byte dev_type;
     public byte dev_function;

     [MarshalAs(UnmanagedType.ByValArray, SizeConst = 25)]
     public byte[] dev_model;

     [MarshalAs(UnmanagedType.ByValArray, SizeConst = 32)]
     public byte[] dev_tag;

}