Argument of type '{header:Header;}' is not assignable to parameter of type 'RequestOptionsArgs'

问题

Im Getting following error while trying to pass header in HTTP.POST/GET request Argument of type '{header:Header;}' is not assignable to parameter of type 'RequestOptionsArgs'. Property 'null' is missing in the type '{header:Header;}'

I have try many solutions but no lock on it.

here my code :

import { Injectable } from '@angular/core';
import { Response, RequestOptions, Headers, Http, URLSearchParams} from '@angular/http';
import { Observable, Subject } from 'rxjs/Rx';  
import {Company} from './companyMaster';
import 'rxjs/add/operator/map';
import "rxjs/Rx";
import 'rxjs/add/operator/toPromise';
import {CommonService} from '../../common.service';
@Injectable()
export class CompanyMasterService {
private GetListActionUrl: string;
private AddEditActionUrl: string;
public headers = new Headers({ 'Content-Type': 'application/json' });
public options = new RequestOptions({ headers: this.headers });
commonService: CommonService;
constructor(private _http: Http) {
    this.commonService = new CommonService();
    this.GetListActionUrl = this.commonService.RootURL + 'Company/GetList';
    this.AddEditActionUrl = this.commonService.RootURL + "Company/AddEdit";
}

private RegenerateData = new Subject<number>();
// Observable string streams
RegenerateData$ = this.RegenerateData.asObservable();

GetList(): Promise<Company[]> {
    return this._http.get(this.GetListActionUrl + "?branchId=" + this.commonService.BranchId)
        .toPromise()
        .then(response => this.extractArray(response))
        .catch();
}

AddEdit(company: Company): any {
    let headers = new Headers({ 'content-type': 'application/json' });
    let body = JSON.stringify({
        'BRANCH_ID': company.BRANCH_ID.toString(),
        'COMPANY_ID': company.COMPANY_ID != null ? company.COMPANY_ID.toString() : null, 'COMPANY_NAME': company.COMPANY_NAME
    });
    let options = new RequestOptions({ headers: headers});

   return this._http.post(this.AddEditActionUrl, body, options)
        .toPromise()
        .then(response => this.extractArray(response))
        .catch();
}

protected extractArray(res: Response, showprogress: boolean = true) {
    let data = res.json();

    return data || [];
}

private getHeaders() {
    // I included these headers because otherwise FireFox
    // will request text/html instead of application/json
    let headers = new Headers();
    headers.append('Accept', 'application/json');
    return headers;
}

}

See above code I have passed header in method AddEdit() but it shows above error i have try many solution like :

• Update Package
• Imported @angular/http
• Tried different way to pass header Tried this solution

i have attached screenshot showing error in Visual studio IDE. See attachement error screenshot please reply as soon as possible.

package.json

{
  "name": "sb-admin-angular4-bootstrap4",
  "version": "1.0.0",
  "license": "MIT",
  "scripts": {
    "ng": "ng",
    "start": "ng serve --ec=true",
    "build": "ng build --prod",
    "gitbuild": "ng build --prod --base='/start-angular/SB-Admin-BS4-Angular-4/master/dist/'",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  },
  "private": true,
  "dependencies": {
    "@angular/common": "^4.0.0",
    "@angular/compiler": "^4.0.0",
    "@angular/core": "^4.0.0",
    "@angular/forms": "^4.0.0",
    "@angular/http": "^4.0.0",
    "@angular/platform-browser": "^4.0.0",
    "@angular/platform-browser-dynamic": "^4.0.0",
    "@angular/router": "^4.0.0",
    "@ng-bootstrap/ng-bootstrap": "^1.0.0-alpha.25",
    "@ngx-translate/core": "^6.0.1",
    "@ngx-translate/http-loader": "0.0.3",
    "core-js": "^2.4.1",
    "font-awesome": "^4.7.0",
    "ionicons": "^3.0.0",
    "ng2-charts": "^1.5.0",
    "rxjs": "^5.1.0",
    "typing": "^0.1.9",
    "zone.js": "^0.8.4"
  },
  "devDependencies": {
    "@angular/cli": "^1.1.3",
    "@angular/compiler-cli": "^4.0.0",
    "@types/jasmine": "2.5.38",
    "@types/node": "~6.0.60",
    "codelyzer": "~2.0.0",
    "jasmine-core": "~2.5.2",
    "jasmine-spec-reporter": "~3.2.0",
    "karma": "~1.4.1",
    "karma-chrome-launcher": "~2.0.0",
    "karma-cli": "~1.0.1",
    "karma-coverage-istanbul-reporter": "^0.2.0",
    "karma-jasmine": "~1.1.0",
    "karma-jasmine-html-reporter": "^0.2.2",
    "karma-phantomjs-launcher": "^1.0.4",
    "protractor": "~5.1.0",
    "ts-node": "~2.0.0",
    "tslint": "~4.5.0",
    "typescript": "~2.2.0",
    "webpack": "^3.0.0"
  }
}

回答1:

I finally solved mine by skipping the RequestOptions object.
I'm using Angular 4 so it may be different for me, but I create an untyped object and pass it into the http method function... -

import { Identifiable, RestRepositoryService, HalResponse } from '../spring-data/rest-repository.service';
import { Injectable } from '@angular/core';
import { HttpClient, HttpHeaders } from '@angular/common/http';
import { ContentTemplate } from '../content-template/content-template.service';

export class ContentItem extends HalResponse {
  id: string;
  name: string;
  description?: string;
  fieldValues: any;
  template: any;
  contentType: any;
}

@Injectable()
export class ContentItemService extends RestRepositoryService<ContentItem>  {

  getContentType(contentItem: ContentItem) {
    return this.http.get(contentItem._links.contentType.href);
  }

  getContentTemplate(contentItem: ContentItem) {
    return this.http.get(contentItem._links.template.href);
  }

  setContentTemplate(contentItem: ContentItem, template: ContentTemplate) {
    const headers = new HttpHeaders({'Content-Type': 'text/uri-list'});
    return this.http.put(contentItem._links.template.href, template._links.self.href, {headers: headers});
  }

  constructor(http: HttpClient) {
    super(http, '/api/contentItems');
  }

}

回答2:

try this method. does this help

 options = new RequestOptions();
            options.headers = new Headers();
            options.headers.append('Content-Type', 'application/json');
            options.headers.append('X-Requested-With', 'XMLHttpRequest');

回答3:

The issue you have is here:

private getHeaders() {
    // I included these headers because otherwise FireFox
    // will request text/html instead of application/json
    let headers = new Headers();
    headers.append('Accept', 'application/json');
    return headers;
}

The implementation of HttpHeaders append() is:

append(name: string, value: string|string[]): HttpHeaders { 
   return this.clone({name, value, op: 'a'}); 
 } 

It returns a clone of your HttpHeaders object. To make your append affect, you need to store it in a variable which is:

headers = headers.append('Accept', 'application/json');

来源：https://stackoverflow.com/questions/44735960/argument-of-type-headerheader-is-not-assignable-to-parameter-of-type-requ