'WebHost' 由于其保护级别而无法访问

Question

I am trying to follow Microsoft's Ocelot API Gateway tutorial ( https://docs.microsoft.com/en-us/dotnet/architecture/microservices/multi-container-microservice-net-applications/implement-api-gateways-with-ocelot ).

First I intialized a new empty ASP.NET Core web app:

dotnet new web

Then I installed the Ocelot dependencies ( https://www.nuget.org/packages/Ocelot/ ):

dotnet add package Ocelot --version 17.0.0

Then I took the code from the tutorial:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using Ocelot.DependencyInjection;
using Ocelot.Middleware;
using System.IO;

namespace MyApp
{
    public class Program
    {
        public static void Main(string[] args)
        {
            BuildWebHost(args).Run();
        }

        public static IWebHost BuildWebHost(string[] args)
        {
            var builder = WebHost.CreateDefaultBuilder(args);

            builder.ConfigureServices(s => s.AddSingleton(builder))
                    .ConfigureAppConfiguration(
                          ic => ic.AddJsonFile(Path.Combine("configuration",
                                                            "configuration.json")))
                    .UseStartup<Startup>();
            var host = builder.Build();
            return host;
        }
    }
}

But then it complains that the WebHost class, called in BuildWebHost method, "is inaccessible due to its protection level". According to Microsoft ( https://docs.microsoft.com/en-us/dotnet/api/microsoft.aspnetcore.webhost ), WebHost "provides convenience methods for creating instances of IWebHost and IWebHostBuilder with pre-configured defaults.", and looks like so:

public static class WebHost
...

Why does it complain that WebHost is inaccessible, when the class is in fact public? What am I missing here?

Answer 1

From the documentation , WebHost is in the namespace Microsoft.AspNetCore . But in your code, It hasn't the using to this namespace.

In Visual Studio, you can try Go to definition on WebHost to discover where the type come.