C#

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO.Ports;
using System.Threading;

namespace SerialCommunicationMCU
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            dataGridView1.Columns.Add("MCUData", "Byte Name");
            dataGridView1.Columns.Add("MCUData", "Byte Value");
        }

        public System.IO.Ports.SerialPort SerialPc;
        

        #region Variables
        public string AvailablePort;
        public string[] Ports = SerialPort.GetPortNames();
        byte[] MCUData = new byte[16];
        #endregion


        private void Connect_Click(object sender, EventArgs e)
        {
            DataGreedByteNameShow();
            SerialConnectandRead();
            ConnectButton.Enabled = false;
            DisconnectButton.Enabled = true;
        }

        private void Disconnect_Click(object sender, EventArgs e)
        {
            SerialPc.Close();
            ConnectButton.Enabled = true;
            DisconnectButton.Enabled = false;
        }

        public void SerialConnectandRead()
        {
            SerialPc = new SerialPort(AvailablePort, 115200, Parity.None, 8, StopBits.One);

            try
            {
                SerialPc.Open();
                SerialPc.DataReceived += new SerialDataReceivedEventHandler(SerialPc_DataReceived);
            }

            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString(), "Serial Port Error");
            }

        }

        private void SerialPc_DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            SerialPc.DiscardNull = false;
            SerialPc.Read(MCUData, 0, 16);
            SerialPc.ReceivedBytesThreshold = 16;
            DataGreedByteValueShow();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            foreach (string port in Ports)
            {
                comboBox1.Items.Add(port);
            }
            DisconnectButton.Enabled = false;
        }

        public void DataGreedByteNameShow()
        {
            dataGridView1.Rows.Add("MCUData[0]");
            dataGridView1.Rows.Add("MCUData[1]");
            dataGridView1.Rows.Add("MCUData[2]");
            dataGridView1.Rows.Add("MCUData[3]");
            dataGridView1.Rows.Add("MCUData[4]");
            dataGridView1.Rows.Add("MCUData[5]");
            dataGridView1.Rows.Add("MCUData[6]");
            dataGridView1.Rows.Add("MCUData[7]");
            dataGridView1.Rows.Add("MCUData[8]");
            dataGridView1.Rows.Add("MCUData[9]");
            dataGridView1.Rows.Add("MCUData[10]");
            dataGridView1.Rows.Add("MCUData[11]");
            dataGridView1.Rows.Add("MCUData[12]");
            dataGridView1.Rows.Add("MCUData[13]");
            dataGridView1.Rows.Add("MCUData[14]");
            dataGridView1.Rows.Add("MCUData[15]");
        }

        private void DataGreedByteValueShow()
        {
            dataGridView1.Rows[0].Cells[1].Value = MCUData[0];
            dataGridView1.Rows[1].Cells[1].Value = MCUData[1];
            dataGridView1.Rows[2].Cells[1].Value = MCUData[2];
            dataGridView1.Rows[3].Cells[1].Value = MCUData[3];
            dataGridView1.Rows[4].Cells[1].Value = MCUData[4];
            dataGridView1.Rows[5].Cells[1].Value = MCUData[5];
            dataGridView1.Rows[6].Cells[1].Value = MCUData[6];
            dataGridView1.Rows[7].Cells[1].Value = MCUData[7];
            dataGridView1.Rows[8].Cells[1].Value = MCUData[8];
            dataGridView1.Rows[9].Cells[1].Value = MCUData[9];
            dataGridView1.Rows[10].Cells[1].Value = MCUData[10];
            dataGridView1.Rows[11].Cells[1].Value = MCUData[11];
            dataGridView1.Rows[12].Cells[1].Value = MCUData[12];
            dataGridView1.Rows[13].Cells[1].Value = MCUData[13];
            dataGridView1.Rows[14].Cells[1].Value = MCUData[14];
            dataGridView1.Rows[15].Cells[1].Value = MCUData[15];
        }

        private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            AvailablePort = comboBox1.SelectedItem.ToString();
        }
    }
}

Public partial class Form_Process : Form
{
   Static Object[ , , ] normW = null;
   //3 dimensional variable

   Private void process(){
       for(int i=0; i<3; i++){
          /*bla..bla..bla..
             //..............................
             //my process is here
             //..............................
         */
          //The result of the process
          //is in variable Normali[ , ].
          //Normali is a 2 dimensional array variable.

          //than..
          normalW[i] = Normali;  //this is where an error take place
       }
   }
}