如何解决从有角度的前端路由到 ASP.NET Core 3.1 后端
So here is my backend .csproj。我正在做一个前端水疗,以角度连接到我在内存数据库中的后端。 I can connect to my database from the URL of my back end application like in the image. 我也可以通过这个 postman sucessfull responses 提出邮递员请求并获得 header ......到目前为止一切都很好。在我的前端有一个问题。我有我的前端角度 service package with the url i use in postman。 in my component i call this method to connect to my service. 不知何故,我无法获得我在邮递员中执行获取请求时获得的“行程”列表。我几乎 80% 确定错误在后端,因为我可以在其他后端应用程序中获取请求。所以我要把我的后端代码放在这里。
我的程序.cs
public class Program
{
public static void Main(string[] args)
{
var host = CreateHostBuilder(args).Build();
using (var scope = host.Services.CreateScope())
using (var context = scope.ServiceProvider.GetService<AppDbContext>())
{
context.Database.EnsureCreated();
}
host.Run();
}
public static IHostBuilder CreateHostBuilder(string[] args) =>
Host.CreateDefaultBuilder(args)
.ConfigureWebHostDefaults(webBuilder =>
{
webBuilder.UseStartup<Startup>();
});
}
我的startup.cs
public class Startup
{
public IConfiguration Configuration { get; }
public Startup(IConfiguration configuration)
{
Configuration = configuration;
}
public void ConfigureServices(IServiceCollection services)
{
services.AddMemoryCache();
services.AddControllers().ConfigureApiBehaviorOptions(options =>
{
});
services.AddDbContext<AppDbContext>(options =>
{
options.UseInMemoryDatabase(Configuration.GetConnectionString("memory"));
});
services.AddScoped<ITripRepository,TripRepository>();
services.AddScoped<ITripService,TripService>();
services.AddScoped<IUnitOfWork,UnitOfWork>();
services.AddAutoMapper(typeof(Startup));
}
public void Configure(IApplicationBuilder app,IWebHostEnvironment env)
{
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
app.UseRouting();
app.UseAuthorization();
app.UseEndpoints(endpoints =>
{
endpoints.MapControllers();
});
}
}
}
我的获取控制器:
[HttpGet]
[ProducesResponseType(typeof(List<TripDTO>),200)]
public async Task<IEnumerable<TripDTO>> GetAllAsync()
{
var trips = await _tripService.ListAsync();
var dtos = _mapper.Map<IEnumerable<Trip>,IEnumerable<TripDTO>>(trips);
return dtos;
}
编辑: 我在尝试获取的列表中执行前端 console.log 时遇到的错误是 enter image description here
EDIT2:AppDbContext 后端
public class AppDbContext : DbContext
{
public DbSet<Trip> Trips { get; set; }
public AppDbContext(DbContextOptions<AppDbContext> options) : base(options) { }
protected override void OnModelCreating(ModelBuilder builder)
{
base.OnModelCreating(builder);
builder.Entity<Trip>().ToTable("Trips");
builder.Entity<Trip>().HasKey(p => p.Id);
builder.Entity<Trip>().Property(p => p.Id).Isrequired().ValueGeneratedOnAdd();
builder.Entity<Trip>().Property(p => p.Key).Isrequired().HasMaxLength(10);
builder.Entity<Trip>().Property(p => p.IsEmpty).Isrequired();
builder.Entity<Trip>().Property(p => p.Orientation).Isrequired();
builder.Entity<Trip>().Property(p => p.LineKey).Isrequired().HasMaxLength(10);
builder.Entity<Trip>().Property(p => p.PathKey).Isrequired().HasMaxLength(10);
builder.Entity<Trip>().Property(p => p.IsGenerated).Isrequired();
builder.Entity<Trip>().Property(p => p.PassingTimes)
.HasConversion(
v => JsonConvert.SerializeObject(v),v => JsonConvert.DeserializeObject<List<PassingTime>>(v));
builder.Entity<Trip>().HasData
(
new Trip { Id = 100,Key="Trip:344",IsEmpty=false,Orientation=false,LineKey="Line:444",PathKey="Path:344",IsGenerated=true },// Id set manually due to in-memory provider
new Trip { Id = 1200,Key="Trip:1344",LineKey="Line:2444",PathKey="Path:3424",IsGenerated=true }
);
}
}
}
编辑 3:
HTML
<!DOCTYPE html>
<html>
<body>
<h4>List of Trips</h4>
<div class="list row">
<div class="col-md-6">
<ul class="list-group">
<li class="list-group-item" *ngFor="let trip of trips; let i = index" [class.active]="i == currentIndex" (click)="setActiveTrip(trip,i)">
{{ trip.key }}
</li>
</ul>
</div>
<div *ngIf="!currentTrip">
<br />
<p>Please click on a trip to see the details...</p>
</div>
<div class="col-md-6">
<div *ngIf="currentTrip">
<h4>Selected Trip Details</h4>
<div>
<div>
<label><strong>Key:</strong></label> {{ currentTrip.key }}
</div>
</div>
</div>
</div>
</div>
</body>
</html>
component.cs
import { Component,OnInit } from '@angular/core';
import { TripService } from 'src/app/masterdataviagem/services/trip-service';
@Component({
selector: 'app-tripslist',templateUrl: './tripslist.component.html',styleUrls: ['./tripslist.component.css']
})
export class TripslistComponent implements OnInit {
trips: any;
currentTrip: any = null;
currentIndex = -1;
key = '';
tripsList:any;
constructor(private tripService:TripService) { this.tripsList=this.tripService.getAll()}
ngOnInit(): void {
this.retrieveTrips();
}
retrieveTrips() {
this.trips= this.tripService.getAll().subscribe(
data => {
this.trips = data;
console.log(data);
},error => {
console.log(error);
});
console.log(this.trips);
}
refreshList() {
this.retrieveTrips();
this.currentTrip = null;
this.currentIndex = -1;
}
setActiveTrip(trip: any,index: number) {
this.currentTrip = trip;
this.currentIndex = index;
}
}
解决方法
也许您必须在后端启用 CORS(我猜是浏览器控制台末尾的“未知错误”,这就是您的 console.log(error))。
您可以尝试使用这个 chrome 扩展来测试:https://chrome.google.com/webstore/detail/allow-cors-access-control/lhobafahddgcelffkeicbaginigeejlf?hl=en。
如果您的后端响应显示启用了扩展程序,则您必须启用 CORS:
https://docs.microsoft.com/en-us/aspnet/core/security/cors?view=aspnetcore-3.1#ecors
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