private void button2_Click(object sender, EventArgs e) { client.BeginLogin(ar => { var a = (NCAsyncResult)ar; if (a.BaseResult == baseResult.Successful) { client.ConnectOMCS("127.0.0.1", 9900); } showResult(a); Invoke(new Action(() => { label3.Text = "id:0000"; })); } , "0000", "123456", null); }