C# [win] สอบถามการส่งค่า string จาก form2 ไป form1 ครับ ลองหลายวิธีแล้วแต่ค่าก็เป็นค่าว่างตลอดเลย

private void btnLogin_Click(object sender, EventArgs e)
        {
            SqlConnection myConnection = default(SqlConnection);
            connection NewConnection = new connection();
            NewConnection.Connection_Today();
            connection.myConnection.Open();

            dt = new DataTable();
            SqlDataAdapter Adapter = default(SqlDataAdapter);

            SqlCommand myCommand = connection.myConnection.CreateCommand();

            myCommand.CommandText = "SELECT * FROM member WHERE username = '" + txtuser.Text + "' and password = '" + txtpass.Text + "' ";
            myCommand.CommandType = CommandType.Text;

            Adapter = new SqlDataAdapter(myCommand);
            Adapter.Fill(dt);

            connection.myConnection.Close();

            string user = "";
            string pass = "";
            string uread = "";
            string uwrite = "";
            string uedit = "";
            string udel = "";
            string role = "";
           
            if (dt.Rows.Count > 0)
            {
                user = dt.Rows[0]["username"].ToString().Trim();
                pass = dt.Rows[0]["password"].ToString().Trim();
                uread = dt.Rows[0]["viewdata"].ToString().Trim();
                uwrite = dt.Rows[0]["write"].ToString().Trim();
                uedit = dt.Rows[0]["edit"].ToString().Trim();
                udel = dt.Rows[0]["del"].ToString().Trim();
            }

            if (user != "" && pass != "")
            {
                if (uread == "Y")
                {
                    if (uwrite == "Y")
                    {
                        if (uedit == "Y")
                        {
                            if (udel == "Y")
                            {
                                role = "all";
                            }
                            else
                            {
                                role = "third";
                            }
                        }
                        else
                        {
                            role = "second";
                        }
                    }
                    else
                    {
                        role = "first";
                    }
                }
                else
                {
                    Application.Exit();
                }

                //MessageBox.Show(role); // มองเห็นค่า แต่ส่งไปอีกฟอร์มไม่เห็น
                this.Hide();

                Customer d = new Customer();
                d.Show();
                
                roles pre = new roles();
                pre.setRoles(role);
            }
            else
            {
                MessageBox.Show("Wrong username or password!!");
            }

            session usr = new session();
            usr.setUser(this.txtuser.Text);
          
            language langs = new language();
            langs.setLang(this.listLanguage.SelectedValue.ToString());
        }

class roles
    {
       private static string strRoles = "";

        public void setRoles(String authen)
        {
            strRoles = authen;
        }

        public static string getRoles()
        {
            return strRoles;
        }
        
    }

public Customer()
        {
            InitializeComponent();
        }
        
        string user = session.getUser();
        string premit = roles.getRoles(); 
        
        private void Customer_Load(object sender, EventArgs e)
        {
            MessageBox.Show(premit);
            if (premit == "third")
            {
                btnDelete.Enabled = false;
            }
            
            System.Threading.Thread.CurrentThread.CurrentCulture = new System.Globalization.CultureInfo("en-US");

            listSearch.Items.Add("custcode");
            listSearch.Items.Add("custgroupcode");
            listSearch.Items.Add("taxid");
            listSearch.SelectedIndex = 0;
            
            BindDataGrid();
        }