Angular 6 HttpClient Post 未命中 DotNet Core 2.2 API 控制器中的 API Post 方法

Question

我已从 MVC/AngularJS 1.x 升级到 DotNet Core 2.2/Angular 6.x。与@Angular/common/http

大多数情况下，这都是轻而易举的事，但 Web API 却让我很受不了。我在几分钟内就开始工作，但我花了一周的时间尝试了一切才能让网络帖子工作。

我在这里所做的事情很容易复制。

1. 进入 Visual Studio 17 并单击“文件/新建项目”

2. 选择已安装/Visual C#/.NET Core

3. 选择模板：ASP.NET core Web Application

4. 在辅助屏幕上，将顶部的下拉菜单设置为 .NET Core 和 ASP.NET Core 2.2

5. 选择红盾“A”角模板

6. 让项目拉下依赖关系并重建。

一切都是 Microsoft 提供的开箱即用演示应用程序，除了：

1. 将按钮添加到屏幕上。

2. 将代码添加到 .ts 以调用 API 控制器

3. 将输入参数添加到控制器中的 get 方法中

4. 向控制器添加一个非常简单的 post 方法

我也在尝试获取 DotNet Core 2.0/Angular 4.x。使用 @angular/http 可以得到完全相同的结果。获取非常简单，但我已经尝试了所有配置才能使帖子正常工作。我也会为其他版本发布类似的帖子。现在，我只是尽我所能地工作并把 AngularJS 1.x 抛在身后。

import { Component, Inject } from '@angular/core';
import { HttpClient, HttpParams, HttpHeaders  } from '@angular/common/http';

@Component({
  selector: 'app-fetch-data',
  templateUrl: './fetch-data.component.html'
})
export class FetchDataComponent {
  public Http: HttpClient;
  public BaseURL: string;
  public HttpOptions = {
    headers: new HttpHeaders({
      'Content-Type': 'application/json'
    })
  };
  public startDateIndex = 0;
  public forecasts: WeatherForecast[] = [];
  public forecast: WeatherForecast = {
    dateFormatted: "3/27/2020",
    temperatureC: 0,
    temperatureF: 32,
    summary: "Cold Post"
  };

  constructor(http: HttpClient, @Inject('BASE_URL') baseUrl: string) {
    this.Http = http;
    this.BaseURL = baseUrl;

    http.get<WeatherForecast[]>(baseUrl + 'api/SampleData/WeatherForecasts')
      .subscribe(result => { this.forecasts = result; }, error => console.error(error));
  }
  public OnClick(pControl: string) {
    //console.log("LogOn.OnClick * pControl=" + pControl);
    switch (pControl) {
      case "Prior":
        this.startDateIndex -= 5;
        this.Http.get<WeatherForecast[]>(this.BaseURL + 'api/SampleData/WeatherForecasts/', { params: new HttpParams().set('startDateIndex', this.startDateIndex.toString()) })
          .subscribe(result => { this.forecasts = result; }, error => console.error(error));
        break;
      case "Next":
        this.startDateIndex += 5;
        this.Http.get<WeatherForecast[]>(this.BaseURL + 'api/SampleData/WeatherForecasts/', { params: new HttpParams().set('startDateIndex', this.startDateIndex.toString()) })
          .subscribe(result => { this.forecasts = result; }, error => console.error(error));
        break;
      case "Post":
        console.log("Post * this.forecast=" + JSON.stringify(this.forecast) + "this.HttpOptions=" + JSON.stringify(this.HttpOptions));
        this.Http.post<WeatherForecast>(this.BaseURL + '/api/SampleData/PostWeatherForecast/', this.forecast, this.HttpOptions);
    }
  }
}

interface WeatherForecast {
  dateFormatted: string;
  temperatureC: number;
  temperatureF: number;
  summary: string;
}

<h1>Weather forecast</h1>

<p>This component demonstrates fetching data from the server.</p>

<p *ngIf="!forecasts"><em>Loading...</em></p>

<table class='table table-striped' *ngIf="forecasts">
  <thead>
    <tr>
      <th>Date</th>
      <th>Temp. (C)</th>
      <th>Temp. (F)</th>
      <th>Summary</th>
    </tr>
  </thead>
  <tbody>
    <tr *ngFor="let forecast of forecasts">
      <td>{{ forecast.dateFormatted }}</td>
      <td>{{ forecast.temperatureC }}</td>
      <td>{{ forecast.temperatureF }}</td>
      <td>{{ forecast.summary }}</td>
    </tr>
  </tbody>
</table>
<button class='btn btn-default pull-left' (click)="OnClick('Prior')">Previous</button>
<button class='btn btn-default pull-left' (click)="OnClick('Next')">Next</button>
<button class='btn btn-default pull-right' (click)="OnClick('Post')">Post</button>

using Microsoft.AspNetCore.Mvc;
using System;
using System.Collections.Generic;
using System.Linq;

namespace NG_22.Controllers
{
    [Route("api/[controller]")]
    public class SampleDataController : Controller
    {
        private static string[] Summaries = new[]
        {
            "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
        };

        [HttpGet("[action]")]
        public IEnumerable<WeatherForecast> WeatherForecasts(int startDateIndex = 0)
        {
            var rng = new Random();
            return Enumerable.Range(1, 5).Select(index => new WeatherForecast
            {
                DateFormatted = DateTime.Now.AddDays(index + startDateIndex).ToString("d"),
                TemperatureC = rng.Next(-20, 55),
                Summary = Summaries[rng.Next(Summaries.Length)]
            });
        }
        [HttpPost("[action]")]
        public WeatherForecast PostWeatherForecast([FromBody] WeatherForecast weatherForecast)
        {
            var forecast = weatherForecast;
            //return weatherForecast;
            return new WeatherForecast()
            {
                DateFormatted = DateTime.Now.ToString("d"),
                TemperatureC = 30,
                Summary = Summaries[2]
            };
        }



        public class WeatherForecast
        {
            public string DateFormatted { get; set; }
            public int TemperatureC { get; set; }
            public string Summary { get; set; }

            public int TemperatureF
            {
                get
                {
                    return 32 + (int)(TemperatureC / 0.5556);
                }
            }
        }
    }
}

Answer 1

解决了！！！！

问题是没有任何订阅。如果没有人在听，就不用费心给《华盛顿邮报》打电话了。我添加了 .subscribe 并且工作正常。

import { Component, Inject } from '@angular/core';
import { HttpClient, HttpParams, HttpHeaders  } from '@angular/common/http';

@Component({
  selector: 'app-fetch-data',
  templateUrl: './fetch-data.component.html'
})
export class FetchDataComponent {
  public Http: HttpClient;
  public BaseURL: string;
  public HttpOptions = {
    headers: new HttpHeaders({
      'Content-Type': 'application/json'
    })
  };
  public startDateIndex = 0;
  public forecasts: WeatherForecast[] = [];
  public forecast: WeatherForecast = {
    dateFormatted: "3/27/2020",
    temperatureC: 0,
    temperatureF: 32,
    summary: "Cold Post"
  };

  constructor(http: HttpClient, @Inject('BASE_URL') baseUrl: string) {
    this.Http = http;
    this.BaseURL = baseUrl;

    http.get<WeatherForecast[]>(baseUrl + 'api/SampleData/WeatherForecasts')
      .subscribe(result => { this.forecasts = result; }, error => console.error(error));
  }
  public OnClick(pControl: string) {
    //console.log("LogOn.OnClick * pControl=" + pControl);
    switch (pControl) {
      case "Prior":
        this.startDateIndex -= 5;
        this.Http.get<WeatherForecast[]>(this.BaseURL + 'api/SampleData/WeatherForecasts/', { params: new HttpParams().set('startDateIndex', this.startDateIndex.toString()) })
          .subscribe(result => { this.forecasts = result; }, error => console.error(error));
        break;
      case "Next":
        this.startDateIndex += 5;
        this.Http.get<WeatherForecast[]>(this.BaseURL + 'api/SampleData/WeatherForecasts/', { params: new HttpParams().set('startDateIndex', this.startDateIndex.toString()) })
          .subscribe(result => { this.forecasts = result; }, error => console.error(error));
        break;
      case "Post":
        console.log("Post * this.forecast=" + JSON.stringify(this.forecast) + "this.HttpOptions=" + JSON.stringify(this.HttpOptions));
        this.Http.post<WeatherForecast>(this.BaseURL + '/api/SampleData/PostWeatherForecast/', this.forecast, this.HttpOptions)
          .subscribe(result => { console.log("Posted" + JSON.stringify(result)); }, error => console.error(error));          
    }
  }
}

interface WeatherForecast {
  dateFormatted: string;
  temperatureC: number;
  temperatureF: number;
  summary: string;
}