Problem running eventhandler

I have a class, which is executed under a button, it makes two select in a bank. I am trying to do this with EventHandler , however, when running the system, it executes, but gives the error in the line: OnDataChange(info);

  

Error Object reference not set to an instance of an object

Followthecodebelow:

publicvoidconsulta(){stringsqltring=@"Data Source=tptspo01sql01.database.windows.net;Initial Catalog=Tptecnologia;Integrated Security=False;User ID=********Password=*********@;Connect Timeout=60;Encrypt=False;TrustServerCertificate=False";
        string _sql = string.Empty;
        SqlConnection sqlcon = new SqlConnection(sqltring);

        string usu, pass;
        int eid, uid;
        usu = textBox1.Text;
        pass = textBox2.Text;

        sqlcon.Open();

            _sql = "SELECT Id_empresa FROM Login WHERE usuario = @usuario AND Passwd = @Passwd";

            SqlCommand cmd = new SqlCommand(_sql, sqlcon);

            cmd.Parameters.Add("@usuario", SqlDbType.VarChar).Value = usu;
            cmd.Parameters.Add("@Passwd", SqlDbType.VarChar).Value = pass;

            eid = (int)cmd.ExecuteScalar();

            _sql = "SELECT Id_usu FROM Login WHERE usuario = @usuario AND Passwd = @Passwd";

            SqlCommand cmd1 = new SqlCommand(_sql, sqlcon);

            cmd1.Parameters.Add("@usuario", SqlDbType.VarChar).Value = usu;
            cmd1.Parameters.Add("@Passwd", SqlDbType.VarChar).Value = pass;                

            uid = (int)cmd1.ExecuteScalar();

        sqlcon.Close();

        Hashtable info = new Hashtable();
        info.Add("eid1", Convert.ToString(eid));
        info.Add("uid1", Convert.ToString(uid));
        OnDataChange(info);

        Tinicial frm2 = new Tinicial();

        frm2.Show();

    }