how to bind gridview programmatically using class file in asp.net

protected void Page_Load(object sender, EventArgs e)
        {
            
                FirstGridViewRow();
                
            
        }

        public void FirstGridViewRow()
        {
            DataTable dt = new DataTable();                    
            dt.Columns.Add("M", typeof(string));
            dt.Columns.Add("L", typeof(string));
            DataRow row = null;
            row = dt.NewRow();
            //row["RowNumber"] = "1";            
            row["M"] = string.Empty;
            row["L"] = string.Empty;
            ViewState["CurrentTable"] = dt;           
            GrdAdmin.DataSource = dt;
            GrdAdmin.DataBind();
        }

    public void GRID(string abcd, string mate)
        {
            string aaaa = abcd;
            string mattype = mate;
            

            if (ViewState["CurrentTable"] != null)
            {
                DataTable dtCurrentTable = (DataTable)ViewState["CurrentTable"];
                DataRow drCurrentRow = null;

                drCurrentRow = dtCurrentTable.NewRow();                         
                drCurrentRow["M"] = aaaa ;
                drCurrentRow["Le"] = mattype ;
                
                dtCurrentTable.Rows.Add(drCurrentRow);
                ViewState["CurrentTable"] = dtCurrentTable;

                GrdAdmin.DataSource = dtCurrentTable;
                GrdAdmin.DataBind();

            }
            else
            {
                Response.Write("ViewState is null");
            }
            SetPreviousData();
        }

public void getinstrumentconnection(int pid, string Email, string instru)
       {
           int partid = pid;
           string mcode = Email;
           string abcd = instru;

           CodeConverter conv = new CodeConverter();
           conv.GRID(mcode , abcd );

           }