Question

我无法让我的函数getData多次工作，第一次使用字段名称＆＃39; a＆＃39;来调用getData，从returnData和getData＆＃39; s中的块返回数据.subscribe被击中。第二次使用字段＆＃39; b＆＃39;来调用getData时，returnData内部的所有内容都按预期工作，但是getData＆＃39; s.subscribe内部的块根本没有被触发。

private getData(field: string): void { 
  this.returnData(field)                                 
    .subscribe((data) => {
    //Handle Data
    //This block is only hit the first time getData is called
  });}

private returnData(field: string): Observable < SomeObj > {         
  let subj: Subject < SomeObj > = new Subject < SomeObj > ();      
  const obj: SomeObj = new SomeObj(field); 
  this.someDataServive.someFunction(field)
    .subscribe(
    (data) => {
      //set properties on obj from data and emit obj
      subj.next(obj);
      //This block is always hit every time getData is called, and the 
      // obj returned from here is correct
     },                                                            
    (err) => {
      subj.next(obj);
    });                                                             
  return (subj.asObservable());                                        
}

Answer 1

原来问题在于我对.subscribe以及何时对.map缺乏了解;主题也是不必要的。更改returnData对map的订阅只是在returnData中持续命中.subscribe块所需的全部内容。

private returnData(field: string): Observable < SomeObj > {              
  const obj: SomeObj = new SomeObj(field); 
  return this.someDataServive.someFunction(field)
    .map(
    (data) => {
      obj.data = data;
      return obj;
    }                                                                                                    
}

从函数返回的订阅Observable仅在第一次工作

1 个答案: