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我正在尝试设置一个使用 NGRX 的应用程序。

当应该加载单个实体时，我无法访问返回的实体参数。

由于无法访问实体参数，我也无法以模式形式加载实体。

首先通过 data.service 从后端调用员工列表

数据.service.ts ：

  getEngineers() {
return this.http.get<Engineer[]>(this.engineersUrl);
}

返回所有注册工程师。

列出所有工程师条目后，engineer-list.componenent.ts 添加 editEngineer 函数：

  editEngineer(engineer: Engineer) {
this.store.dispatch(new engineerActions.LoadEngineer(engineer.id));
this.openEditDialog(engineer);
console.log(engineer.id, 'selectedEngineersId');
 }

 openEditDialog({ Name, LastName, PhoneNumber, Company, Country }: Engineer) 
{
const dialogRef = this.dialog.open(EgnineerEditDialogComponent, {
  disableClose: true,
  width: '300px',
  data: {
    Name, LastName, PhoneNumber, Company, Country
  }
 });
}

然后 loadEngineer$() 效果发生：

@Effect()
loadEngineer$: Observable<Action> = this.actions$.pipe(
    ofType<engineerActions.LoadEngineer>(
        engineerActions.EngineerActionTypes.LOAD_ENGINEER
    ),
    mergeMap((action: engineerActions.LoadEngineer) =>
        this.dataService.getEngineerById(action.payload).pipe(
            map(
                (engineer: Engineer) =>
                new engineerActions.LoadEngineerSuccess(engineer)
            ),
            catchError(err => of(new engineerActions.LoadEngineerFail(err)))
        )
    ),
);

data.service 调用 getEngineerById()：

  getEngineerById(payload: number): Observable<Engineer> {
     console.log(`${this.engineerUrl}?id=${payload}`);
      return this.http.get<Engineer>(`${this.engineerUrl}?id=${payload}`);
  }

它从 php mysql 请求中返回所选工程师的 json 响应：

$result = $conn->query($sql);

$emparray = $result->fetch_all( MYSQLI_ASSOC );
echo json_encode( $emparray );

下一步由带有 LOAD_ENGINEER_SUCCESS 的减速器执行

        case engineersActions.EngineerActionTypes.LOAD_ENGINEER_SUCCESS: {
        console.log(action.payload.id, ' - ID of the selected engineer object');
        return engineerAdapter.addOne(action.payload, {
            ...state,
           selectedEngineerId: action.payload.id,
           loading: false,
           loaded: true
        });

    }

这里的问题是控制台记录了减速器的响应

console.log(action.payload.id, ' - ID of the selected engineer object');

undefined " - ID of the selected engineer object" 控制台记录“action.payload”返回时返回：

[{…}]
0:
Company: "Andys Shack"
Country: "EE"
LastName: "Franklichtenshtein    "
Name: "Angus    "
PhoneNumber: "123123123123    "
Registered: "2019-03-09 01:33:28"
id: "19"
__proto__: Object
length: 1
__proto__: Array(0)

NGRX 也返回错误：

entity.js:106 @ngrx/entity: The entity passed to the `selectId` implementation returned undefined. You should probably provide your own `selectId` implementation. The entity that was passed: [{…}]0: {id: "19", Name: "Angus    ", LastName: "Franklichtenshtein    ", PhoneNumber: "123123123123    ", Country: "EE", …}length: 1__proto__: Array(0) The `selectId` implementation: function (instance) { return instance.id; }
4

1 回答 1

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有效负载是一个数组，而不是一个对象。

action.payload[0].id
于 2019-03-14T19:00:03.167 回答