为什么将“ Environment.CurrentDirectory”设置为“ C：\\ Program Files \\ IIS Express”？

Question

我在https://www.c-sharpcorner.com/article/building-api-gateway-using-ocelot-in-asp-net-core/中关注API网关示例

然后，我创建一个空的asp.net Web API应用程序，并按照上述链接中所述的步骤进行操作。

我在Program.cs文件中的Main（）函数是：

    public static void Main(string[] args)
    {
        IWebHostBuilder builder = new WebHostBuilder();
        builder.ConfigureServices(s =>
        {
            s.AddSingleton(builder);
        });
        builder.UseKestrel()
               .UseContentRoot(Directory.GetCurrentDirectory())
               .UseStartup<Startup>()
               .UseUrls("http://localhost:9000");

        var host = builder.Build();
        host.Run();
    }

另外，我的Startup.cs文件具有以下代码：

public class Startup
{
    public Startup(IHostingEnvironment env)
    {
        var builder = new Microsoft.Extensions.Configuration.ConfigurationBuilder();
        builder.SetBasePath(Environment.CurrentDirectory)
               .AddJsonFile("configuration.json", optional: false, reloadOnChange: true)
               .AddEnvironmentVariables();

        Configuration = builder.Build();
    }

    public IConfigurationRoot Configuration { get; private set; }

    // This method gets called by the runtime. Use this method to add services to the container.
    // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
    public void ConfigureServices(IServiceCollection services)
    {
        Action<ConfigurationBuilderCachePart> settings = (x) =>
        {
            x.WithMicrosoftLogging(log =>
            {
                log.AddConsole(LogLevel.Debug);

            }).WithDictionaryHandle();
        };
        services.AddOcelot();
    }

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public async void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
        await app.UseOcelot();
    }
}

运行代码时，出现file错误configuration.json NOT FOUND。当我在上述函数中检查当前目录的源代码时，我看到Directory.GetCurrentDirectory()返回PATH C:\\Program Files\\IIS Express而不是当前项目目录。

我的问题是为什么将路径设置为IIS目录？我怎样才能解决这个问题 ？

Answer 1

这是Github中报告的ASP.NET Core 2.2中的错误，Microsoft ASP.NET Core团队提供了以下解决方案，他们将在ASP.NET Core的功能版本中添加此解决方案。

编写如下的帮助器类：

public class CurrentDirectoryHelpers
{
    internal const string AspNetCoreModuleDll = "aspnetcorev2_inprocess.dll";

    [System.Runtime.InteropServices.DllImport("kernel32.dll")]
    private static extern IntPtr GetModuleHandle(string lpModuleName);

    [System.Runtime.InteropServices.DllImport(AspNetCoreModuleDll)]
    private static extern int http_get_application_properties(ref IISConfigurationData iiConfigData);

    [System.Runtime.InteropServices.StructLayout(System.Runtime.InteropServices.LayoutKind.Sequential)]
    private struct IISConfigurationData
    {
        public IntPtr pNativeApplication;
        [System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.BStr)]
        public string pwzFullApplicationPath;
        [System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.BStr)]
        public string pwzVirtualApplicationPath;
        public bool fWindowsAuthEnabled;
        public bool fBasicAuthEnabled;
        public bool fAnonymousAuthEnable;
    }

    public static void SetCurrentDirectory()
    {
        try
        {
            // Check if physical path was provided by ANCM
            var sitePhysicalPath = Environment.GetEnvironmentVariable("ASPNETCORE_IIS_PHYSICAL_PATH");
            if (string.IsNullOrEmpty(sitePhysicalPath))
            {
                // Skip if not running ANCM InProcess
                if (GetModuleHandle(AspNetCoreModuleDll) == IntPtr.Zero)
                {
                    return;
                }

                IISConfigurationData configurationData = default(IISConfigurationData);
                if (http_get_application_properties(ref configurationData) != 0)
                {
                    return;
                }

                sitePhysicalPath = configurationData.pwzFullApplicationPath;
            }

            Environment.CurrentDirectory = sitePhysicalPath;
        }
        catch
        {
            // ignore
        }
    }
}

然后按如下所示在SetCurrentDirectory()方法中调用该方法Main：

public static void Main(string[] args)
{

     CurrentDirectoryHelpers.SetCurrentDirectory(); // call it here


    IWebHostBuilder builder = new WebHostBuilder();
    builder.ConfigureServices(s =>
    {
        s.AddSingleton(builder);
    });
    builder.UseKestrel()
           .UseContentRoot(Directory.GetCurrentDirectory())
           .UseStartup<Startup>()
           .UseUrls("http://localhost:9000");

    var host = builder.Build();
    host.Run();
}

现在一切正常！