Question

我有一个角度2应用程序。从rxjs-5.0.0-beta.12升级到rxjs-5.1.0但现在低于this.http.get(...).map()则显示错误。

提供的参数与呼叫目标的任何签名
都不匹配

import { Http, Headers } from '@angular/http';
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/catch';

export class BaseService {
    private baseUrl: string = 'http://someserver:8080/somedb';

    constructor(public http: Http) {}

    doGet(url: string, headers?: Headers): Observable<any> {
        if(headers) {
            return this.http.get(this.baseUrl+url, {headers: headers}).map(response => {

            }, err => {

            });

        }
    }

}

仅在添加.map()时出现错误，在发布中发生了哪些变化？

完整的IDE消息：

[ts] Supplied parameters do not match any signature of call target.
Applies a given project function to each value emitted by the source
Observable, and emits the resulting values as an Observable.

<span class="informal">Like Array.prototype.map(),
it passes each source value through a transformation function to get
corresponding output values.</span>

<img src="./img/map.png" width="100%">

Similar to the well known Array.prototype.map function, this operator
applies a projection to each value and emits that projection in the output
Observable.

@example <caption>Map every every click to the clientX position of that click</caption>
var clicks = Rx.Observable.fromEvent(document, 'click');
var positions = clicks.map(ev => ev.clientX);
positions.subscribe(x => console.log(x));

@see {@link mapTo}
@see {@link pluck}

@return {Observable<R>} An Observable that emits the values from the source
Observable transformed by the given project function.
@method map
@owner Observable

(property) Observable<Response>.map: <T, R>() => any

Answer 1

Observable.map只接受一个回调函数作为参数。您应该将错误回调放在using System; using System.Text; using LibUsbDotNet; using LibUsbDotNet.Main; namespace Examples { internal class ReadPolling { public static UsbDevice MyUsbDevice; #region SET YOUR USB Vendor and Product ID! public static UsbDeviceFinder MyUsbFinder = new UsbDeviceFinder(1234, 1); #endregion public static void Main(string[] args) { ErrorCode ec = ErrorCode.None; try { // Find and open the usb device. MyUsbDevice = UsbDevice.OpenUsbDevice(MyUsbFinder); // If the device is open and ready if (MyUsbDevice == null) throw new Exception("Device Not Found."); // If this is a "whole" usb device (libusb-win32, linux libusb-1.0) // it exposes an IUsbDevice interface. If not (WinUSB) the // 'wholeUsbDevice' variable will be null indicating this is // an interface of a device; it does not require or support // configuration and interface selection. IUsbDevice wholeUsbDevice = MyUsbDevice as IUsbDevice; if (!ReferenceEquals(wholeUsbDevice, null)) { // This is a "whole" USB device. Before it can be used, // the desired configuration and interface must be selected. // Select config #1 wholeUsbDevice.SetConfiguration(1); // Claim interface #0. wholeUsbDevice.ClaimInterface(0); } // open read endpoint 1. UsbEndpointReader reader = MyUsbDevice.OpenEndpointReader(ReadEndpointID.Ep01); byte[] readBuffer = new byte[1024]; while (ec == ErrorCode.None) { int bytesRead; // If the device hasn't sent data in the last 5 seconds, // a timeout error (ec = IoTimedOut) will occur. ec = reader.Read(readBuffer, 5000, out bytesRead); if (bytesRead == 0) throw new Exception(string.Format("{0}:No more bytes!", ec)); Console.WriteLine("{0} bytes read", bytesRead); // Write that output to the console. Console.Write(Encoding.Default.GetString(readBuffer, 0, bytesRead)); } Console.WriteLine("\r\nDone!\r\n"); } catch (Exception ex) { Console.WriteLine(); Console.WriteLine((ec != ErrorCode.None ? ec + ":" : String.Empty) + ex.Message); } finally { if (MyUsbDevice != null) { if (MyUsbDevice.IsOpen) { // If this is a "whole" usb device (libusb-win32, linux libusb-1.0) // it exposes an IUsbDevice interface. If not (WinUSB) the // 'wholeUsbDevice' variable will be null indicating this is // an interface of a device; it does not require or support // configuration and interface selection. IUsbDevice wholeUsbDevice = MyUsbDevice as IUsbDevice; if (!ReferenceEquals(wholeUsbDevice, null)) { // Release interface #0. wholeUsbDevice.ReleaseInterface(0); } MyUsbDevice.Close(); } MyUsbDevice = null; // Free usb resources UsbDevice.Exit(); } // Wait for user input.. Console.ReadKey(); } } } }或使用subscribe()

catch

Observable.map - 提供的参数与调用目标的任何签名都不匹配

1 个答案: