在某些情况下，我正在使用Angular和.net开发一个Web应用程序，我从数据库中检索一些数据，并能够使用搜索栏搜索它。
我的问题是在CORS上，我在.net上实现了它，我可以使用GET方法，但我不能使用PUT方法和其他方法，如POST和DELETE，但我可以在Postman上做到这一点（但这是正确的，因为从我所看到的Postman在CORS方面没有限制）。我在webconsole上遇到了这个错误。

Access to XMLHttpRequest at 'https://localhost:44312/api/Collaborator/7' from origin 'http://localhost:4200' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.

这是我的.net代码

using System;
using FluentValidation.AspNetCore;
using MediatR;
using Microsoft.AspNetCore.Authentication.Negotiate;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using OB.TimeSheet.Application;
using OB.TimeSheet.Application.Common.Interfaces;
using OB.TimeSheet.Infrastructure;
using OB.TimeSheet.Infrastructure.Data;
using OB.TimeSheet.src.Application.Common.Interfaces;
using OB.TimeSheet.WebUI.Services;

 namespace OB.TimeSheet.WebUI
{
    public class Startup
  {
    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }

    public IConfiguration Configuration { get; }

    public void ConfigureServices(IServiceCollection services)
    {
        services.AddApplication();
        services.AddInfrastructure(Configuration);

        services.AddDbContext<OBDbContext>(options =>
            options.UseSqlServer(Configuration.GetConnectionString("MyDbContext")));

        services.AddScoped<IApplicationDbContext, OBDbContext>();

        services.AddRouting();

        services.AddCors(options =>
        {
            options.AddPolicy("OBTimesheetPolicy", builder =>
            {
                builder.WithOrigins("http://localhost:4200") // Add your Angular application's origin
                    .AllowAnyHeader()
                    .AllowAnyMethod()
                    .AllowCredentials();
            });
        });

        services.AddMediatR(typeof(Startup));

        services.AddSingleton<ICurrentUserService, CurrentUserService>();

        services.AddHttpContextAccessor();

        services.AddHealthChecks();

        services.AddSwaggerGen();

        services.AddControllers()
            .AddFluentValidation();

        services.AddFluentValidationAutoValidation()
            .AddFluentValidationClientsideAdapters();

        services.AddAuthentication(NegotiateDefaults.AuthenticationScheme)
            .AddNegotiate();

        services.AddAuthorization(options =>
        {
            options.AddPolicy("AllUsers", policy => policy.RequireAuthenticatedUser());
        });

        services.AddRazorPages();

        services.Configure<ApiBehaviorOptions>(options =>
        {
            options.SuppressModelStateInvalidFilter = true;
        });
    }

    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }
        else
        {
            app.UseExceptionHandler("/Error");
            app.UseHsts();
        }

        app.UseHttpsRedirection();
        app.UseStaticFiles();

        app.UseRouting();

        app.UseCors("OBTimesheetPolicy");

        app.UseAuthentication();

        app.UseAuthorization();

        app.UseEndpoints(endpoints =>
        {
            endpoints.MapControllers();

            endpoints.MapControllerRoute(
                name: "default",
                pattern: "{controller}/{action=Index}/{id?}");

            endpoints.MapControllerRoute(
                name: "api",
                pattern: "api/{controller}/{action=Index}/{id?}");

            endpoints.MapRazorPages();
        });

        app.UseHealthChecks("/health");

        app.UseSwagger();
        app.UseSwaggerUI(options =>
        {
            options.DocumentTitle = "OB.TimeSheet API";
            options.RoutePrefix = string.Empty;

            options.DisplayOperationId();
            options.DisplayRequestDuration();

            options.SwaggerEndpoint("/swagger/v1/swagger.json", "OB.TimeSheet API V1");
        });
    }
}

}
和Angular

import { Injectable } from '@angular/core';
import { Collaborator, Team } from 'src/app/models/api/api.models';
import { HttpClient } from '@angular/common/http';
import { Observable } from 'rxjs';
import { environment } from 'src/environments/environment';

@Injectable({
  providedIn: 'root',
})
export class ApiService {

  private readonly options = {withCredentials: true};  
  private readonly apiUrl: string = environment.apiUrl;

  constructor(private httpClient: HttpClient) {}

  getCollaborator(): Observable<Collaborator[]> {
    return this.get<Collaborator[]>('/Collaborator');
  }

  updateCollaborator(collaborator: Collaborator): Observable<void> {
    return this.put<void>(`/Collaborator/${collaborator.id}`, collaborator);
  }

  getTeam(): Observable<Team[]> {
    return this.get<Team[]>('/Team');
  }

  private get<T>(endpoint: string): Observable<T> {
    return this.httpClient.get<T>(this.apiUrl + endpoint, this.options);
  }

  private put<T>(endpoint: string, body: any): Observable<T> {
    return this.httpClient.put<T>(this.apiUrl + endpoint, body, this.options);
  }
}