您好我正在尝试使用<Viewbox Width="16" Height="16" Child="{StaticResource mPencilCanvas}"/>
中的HTTP模块发送获取请求。
Angular2（1.5）中的所有内容都很好，但Typescript在控制台中显示以下错误：
ChromeEXCEPTION: Error during instantiation of EntryList!. ORIGINAL
EXCEPTION: TypeError: Cannot read property 'merge' of undefined
ORIGINAL STACKTRACE: TypeError: Cannot read property 'merge' of undefined
at mergeOptions (angular2.dev.js:27991)
at execute.Http.get (angular2.dev.js:28052)
at EntryService.getEntries (services.js:17)
at new EntryList (entry-list.js:20)
/// <reference path="../typings/angular2/angular2.d.ts" />
import { Http, Observable } from "angular2/angular2"
export class EntryService {
private _entries: Array<string>;
private _http : Http;
constructor() {
this._entries = ["test1", "test2", "test3"];
this._http = new Http;
}
get Entries() : Array<string> {
return this._entries;
}
getEntries()
{
console.log(this._http);
return this._http.get('http://localhost:53338/api/decisions')
.toRx()
.map((response) => {
response.json()
});
}
}
/// <reference path="../typings/angular2/angular2.d.ts" />
/// <reference path="../modules/services.ts" />
import { Component, View, NgFor } from "angular2/angular2"
import { EntryService } from "modules/services"
@Component({
selector: 'entry-list'
})
@View({
directives: [ NgFor ],
templateUrl: "../views/entry-list.html"
})
export class EntryList {
entries: Array<string>;
constructor(public service: EntryService) {
this.entries = this.service.Entries;
this.service.getEntries().subscribe((response) => {
console.log(response);
});
}
}
/// <reference path="typings/angular2/angular2.d.ts" />
/// <reference path="components/entry-list.ts" />
/// <reference path="modules/services.ts" />
import { Component, View, bootstrap, NgFor } from "angular2/angular2"
import { EntryList } from "components/entry-list"
import { EntryService } from "modules/services"
@Component({
selector : "app",
bindings: [ EntryService ]
})
@View({
directives: [ EntryList ],
templateUrl: "views/app.html"
})
class App {
constructor() {
console.log('hit');
}
}
bootstrap(App);
我确实查看了<html>
<head>
<title>SCM</title>
<script src="https://github.jspm.io/jmcriffey/bower-traceur-runtime@0.0.88/traceur-runtime.js"></script>
<script src="https://jspm.io/system@0.16.js"></script>
<script src="https://code.angularjs.org/2.0.0-alpha.34/angular2.dev.js"></script>
</head>
<body>
<app></app>
<script>System.import('app')</script>
</body>
</html>
网站上的API文档，但看不出什么错误。
angular.io/// <reference path="../typings/angular2/angular2.d.ts" />
import { Http, Observable, httpInjectables } from "angular2/angular2"
export class EntryService {
private _entries: Array<string>;
constructor(private http: Http) {
this._entries = ["test1", "test2", "test3"];
}
get Entries() : Array<string> {
return this._entries;
}
getEntries()
{
console.log(this.http);
return this.http.get('http://localhost:53338/api/decisions')
.toRx()
.map((response) => {
response.json()
});
}
}
/// <reference path="../typings/angular2/angular2.d.ts" />
/// <reference path="../modules/services.ts" />
import { Component, View, NgFor, Http, httpInjectables } from "angular2/angular2"
import { EntryService } from "modules/services"
@Component({
selector: 'entry-list',
bindings : [ Http, httpInjectables ]
})
@View({
directives: [ NgFor ],
templateUrl: "../views/entry-list.html"
})
export class EntryList {
entries: Array<string>;
constructor(public service: EntryService) {
this.entries = this.service.Entries;
this.service.getEntries().subscribe((response) => {
console.log(response);
});
}
}
对/// <reference path="typings/angular2/angular2.d.ts" />
/// <reference path="components/entry-list.ts" />
/// <reference path="modules/services.ts" />
import { Component, View, bootstrap, NgFor, Http, httpInjectables } from "angular2/angular2"
import { EntryList } from "components/entry-list"
import { EntryService } from "modules/services"
@Component({
selector : "app",
bindings: [ EntryService, Http, httpInjectables ]
})
@View({
directives: [ EntryList ],
templateUrl: "views/app.html"
})
class App {
constructor() {
console.log('hit');
}
}
bootstrap(App);
编辑：我的services.ts文件已更改以使其正常工作：
index.html答案 0 :(得分：10)
你不应该自己实例化Http，而是注入它：
public constructor(http : Http) {
this.http = http;
}
文档说：
Http作为可注入类提供，具有执行http请求的方法。
因此，如果您自己实例化，我不确定结果是什么，但由于某些内部未定义，它无法以某种方式设法执行get请求。
编辑：添加更多来源。
@Injectable()
export class Http {
constructor(protected _backend: ConnectionBackend, protected _defaultOptions: RequestOptions) {}
/**
* Performs a request with `get` http method.
*/
get(url: string, options?: RequestOptionsArgs): EventEmitter {
return httpRequest(this._backend, new Request(mergeOptions(this._defaultOptions, options, RequestMethods.GET, url)));
}
}
这里我从github repo中添加了一小部分Http类。你可以看到_backend和_defaultOptions是在你没有给出的构造函数中给出的，方法get（）将根据options参数和构造函数中给出的_defaultOptions构建请求的选项，因为你没有提供其中，我相信它会在你可以在这里找到的mergeOptions调用中崩溃：
function mergeOptions(defaultOpts, providedOpts, method, url): RequestOptions {
var newOptions = defaultOpts;
if (isPresent(providedOpts)) {
// Hack so Dart can used named parameters
newOptions = newOptions.merge(new RequestOptions({
method: providedOpts.method,
url: providedOpts.url,
search: providedOpts.search,
headers: providedOpts.headers,
body: providedOpts.body,
mode: providedOpts.mode,
credentials: providedOpts.credentials,
cache: providedOpts.cache
}));
}
if (isPresent(method)) {
return newOptions.merge(new RequestOptions({method: method, url: url}));
} else {
return newOptions.merge(new RequestOptions({url: url}));
}
}
在函数的最后一个if / else处。有关更多信息，源文件位于here。
答案 1 :(得分：2)
你真的想为CRUD / HTTP请求使用另一个库吗？ **
我强烈推荐es6 de-facto fetch。它不仅是 我认为现在比angular2 / http更简单，但也是 标准现在和将来的版本。
**它开箱即用于safari，chrome，ie-edge和firefox。