using System;

using System.Runtime.InteropServices;

​

public class Program

{

    public void Main()

{

    HeaderCommand data = new HeaderCommand();

    data.byteSize = new byte[20];

    data.byteSize[0] = 1;

    data.byteSize[19] = 19;

    data.val.robotName = new char[20];

    data.val.robotName[0] = 'A';

    data.val.robotName[19] = 'Z';

    data.val.robotVersion = new char[12];

    data.val.robotVersion[0] = 'A';

    data.val.robotVersion[11] = 'Z';

    data.val.stepInfo = 3;

    data.val.sof = 4;

    data.val.invokeId = 5;

    data.val.dataSize=6;

    data.val.reserved = new char[10];

    data.val.reserved[0] = 'A';

    data.val.reserved[9] = 'Z';

    data.val.cmdId=7;

    var b= StructureToByte(data);

    Console.WriteLine(b.Length);

}

​

// Define other methods and classes here

public struct HeaderCommand

    {

        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 20)] public byte[] byteSize;

        public HeaderCommandStruct val;

​

    }

​

    public struct HeaderCommandStruct

    {

        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 20)] public char[] robotName;

        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 12)] public char[] robotVersion;

        public byte stepInfo;

        public byte sof;

        public int invokeId;

        public int dataSize;

        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 10)] public char[] reserved;

        public int cmdId;

    }

    public static byte[] StructureToByte(HeaderCommand data)

    {

        int dataSize = Marshal.SizeOf(data);

        byte[] arr = new byte[dataSize];

​

        IntPtr ptr = Marshal.AllocHGlobal(dataSize);

        Marshal.StructureToPtr(data, ptr, false);

        Marshal.Copy(ptr, arr, 0, dataSize);

        Marshal.FreeHGlobal(ptr);

        return arr;

    }

}