Question

我有Angular2应用程序，可注射服务，类，异步后端调用，什么不是，这不是由be编写的。但不知何故，我被要求在那里提供一种以前没有实现的会话控制。所以我创建了一个新课程，一个非常基础的课程。

//EnvConfig.ts:

export class SessionParameters {

private static userId: string = 'EMPTY_USER_ID';
private static userLogin: string = 'EMPTY_USER_LOGIN';
private static callEDUID: string = 'EMPTY_CALL_ID'

static setUserID(userid: string): void {
    SessionParameters.userId = userid;
}

static setUserLogin(usrLogin: string): void {
    SessionParameters.userLogin = usrLogin;
}

static setCurrentCallId(eduid: string): void {
    SessionParameters.callEDUID = eduid;
}

static getUserID(): string {
    return SessionParameters.userId;
}

static getUserLogin(): string {
    return SessionParameters.userLogin;
}

static getCurrentCallId(): string {
    return SessionParameters.callEDUID;
}

static clearSession(): void {
    SessionParameters.userId = 'EMPTY_USER_ID';
    SessionParameters.userLogin = 'EMPTY_USER_LOGIN';
    SessionParameters.callEDUID = 'EMPTY_CALL_ID';
}

这里没什么特别的，好吧。现在......我想在应用程序初始化时添加会话参数，所以我这样做了：

//app.ts:

import { SessionParameters } from 'components/EnvConfig';


@Component({
selector: 'http-app',
template: `
<div class="tcs-parent-container" [ngClass]='cardProduct'>
  <contact-details 
    [cId]='cId'>
  </contact-details>`


class HttpApp {
  constructor (public siebel: CustomerService) {}

....
PostMessageHandler(eventJson: any): void {
...
console.log("Login: "+SessionParameters.getUserLogin());
SessionParameters.setUserLogin(eventJson.params.userLogin);
...
}

好的，这实际上运行正常，因为我在浏览器控制台中看到：“登录：EMPTY_USER_LOGIN”来自传入的事件交互。如您所见，有一个“联系人详细信息”选择器，子组件将呈现在其中：

//ContactForm.ts:
import { CustomerService } from 'components/CustomerService';
import { Observable } from 'rxjs/Observable';
import 'rxjs/Rx';

...
constructor (public crv: CustomerService)
...
/*
  subscribe on request's responce execution with implicit observer creation:
    - first parameter: function to invoke for each element in the observable sequence - in our case it's responce from http
    - second parameter: function to invoke upon exceptional termination of the observable sequence
    - third parameter: function to invoke upon graceful termination of the observable sequence 
*/
this.crv
  .searchBackEnd(id, 'contact')
  .subscribe(
    (response: any) => this.renderApplet(response),
    (error: any) => this.crv.logMessage('contact-details',`${this.cId}`,'backend_call_request_error:${error}'),
    () => this.crv.logMessage('contact-details',`${this.cId}`,'backend_call_completed')
  );

...

在子组件中，我们使用我们的服务来获取后端的东西。除了这部分之外，服务与我无关：

  ...
import { BackEndURL, GeneralSettings, SessionParameters } from 'components/EnvConfig';
import 'rxjs/Rx';
...
//method for writig logs back into back-end
logMessage(entityName: string, identifier: string, msg: string): void {

console.log("login_srv: "+SessionParameters.getUserLogin());

//check the switcher
if(GeneralSettings.SERVICE_LOG_ON){

  // time management
  let currDate: Date = new Date();
  let hrs: number = currDate.getHours();
  let mnt: number = currDate.getMinutes();
  let sec: number = currDate.getSeconds();
  let mls: number = currDate.getMilliseconds();
  let timeStr: string = `${hrs}:${mnt}:${sec}:${mls}`;

  // calling http. No callback on subscription
          this.queryWithoutJSONTransform(`${BackEndURL.SERVICE_LOG_ENDPOINT_BRANCH}`, [
    `msg=${SessionParameters.getUserLogin()}||${entityName}||${identifier}||${msg}||${timeStr}||`
  ]).subscribe();

} else {
  //do nothing
}

嗯，问题是，SessionParameters.getUserLogin在这里返回undefined。

总而言之，我看到了这个控制台输出：

...
 app.ts:109 Login: EMPTY_USER_LOGIN
2016-12-28 12:35:15.815 CustomerService.ts:49 login_srv: undefined
2016-12-28 12:35:15.821 CustomerService.ts:49 login_srv: undefined
2016-12-28 12:35:15.895 CustomerService.ts:49 login_srv: undefined
...

任何人都可以解释为什么私有静态成员在我的服务中是不可访问的，除非由setter特别设置？它通常工作正常，但问题恰恰在于会话控制类的初始静态成员值。

具有私有静态成员的Typecript类+ Angular 2

0 个答案: