Angular 7 HttpClient put 请求参数将空值发送到端点

Question

我有一个带有此 Put 请求方法的 Angular 服务：

put(peopleFieldID: number, peopleFieldName: string): Observable<number> {
let params = new HttpParams();
params = params.append("peopleFieldID", peopleFieldID.toString());
params = params.append("peopleFieldName", peopleFieldName);
return this.http
  .put<number>(this.url, { params: params })
  .pipe(catchError(this._errorHandling.handleError.bind(this)));}

以上内容在我的 .net 核心 API 上命中此端点：

    [Authorize(Roles = "Client")]
    [Route("")]
    [HttpPut]
    public IActionResult C_Update(int peopleFieldID, string peopleFieldName )
    {
        //Make call to the proper repo method.
        return Json(_peopleFieldRepo.C_Update(peopleFieldID, peopleFieldName));
    }

两个参数，peopleFieldID 和 peopleFieldName，始终为 0 和 null。我已经查明 Angular 前端正确发送参数，但后端无法识别它们。我还有许多其他端点，可以正常工作。

Answer 1

您需要使用 HttpParams 设置查询参数，如果没有，则需要为有效负载传递null：

const params = new HttpParams()
            .set('peopleFieldID', peopleFieldID.toString())
            .set('peopleFieldName', peopleFieldName);
// if you have a payload to pass you can do that in place of null below
return this.http
  .put<number>(this.url, null, { params: params })
  .pipe(catchError(this._errorHandling.handleError.bind(this)));}