Angular Http Post 到 Json 显示 [object Object]

Question

我需要关于我的个人项目的帮助。我正在尝试使用 Angular HTTP post 方法然后我得到了这种错误。当我添加新数据时，调用addStudent 并重新加载页面，semester 列返回/显示[object Object]。除semester 外，其他列均正常工作。

//file name: app.service.ts
 addStudent(newId: string, newName: string, newYear: string, newSemester: string, newScore: string): Observable<any>
    {
        return this.http.post("http://localhost:3000/Student", {id: newId, name: newName, year: newYear, semester: newSemester, score: newScore});
    }

//file name : app.component.ts
addStudent(newId: string, newName: string, newYear: string, newSemester: string, newScore: string)
  {
    this.stockService.addStudent(newId, newName, newYear, newSemester, newScore).subscribe();
    console.log(newSemester);
  }

<!--file name: app.component.html-->
<tr *ngFor="let Student of Student" [attr.id]="Student.id">
    <td>{{Student.id}}</td> 
    <td>{{Student.name}}</td>
    <td>{{Student.year}}</td>
    <td>{{Student.semester}}</td>
    <td>{{Student.score}}</td>
  </tr>
</table>
</h1>

<h3>ADD NEW</h3>
<br>ID: <input #newId/>
<br>Name: <input #newName/>
<br>Year: <input #newYear/>
<br>Semester: <input #newSemester/>
<br>Score: <input #newScore/>
<br><button type="button" role="button" (click)="addStudent(newId.value, newName.value, newYear.value, newSemester, newScore.value)">ADD</button>

添加新行时 Json 看起来像这样

{ "id": "a", "name": "a", "year": "a", "semester": {}, "score": "a" }

如果需要更多的 sn-ps，请告诉我。

谢谢。

Answer 1

这只是错字。

<button type="button" role="button" (click)="addStudent(newId.value, newName.value, newYear.value, newSemester, newScore.value)">ADD</button>

看到你忘记了 newSemester 的 .value。

改为：

<button type="button" role="button" (click)="addStudent(newId.value, newName.value, newYear.value, newSemester.value, newScore.value)">ADD</button>