c# - 无法在我的 Asp.Net Core 项目中的帮助程序类中访问 Session 对象

Question

我正在尝试访问我的 ASP.NET Core 2.1 项目中的帮助程序类中的 HttpContext.Session 对象。

当我尝试访问 HttpContext.Session 时出现以下错误。

CS0120 An object reference is required for the non-static field, method, or property 'HttpContext.Session'

在 .NET 4.x ASP.NET 中，可以通过“HttpContext.Current.Session”轻松访问它。

这是我的类(class):

 public class MySession
 {

    public void Foo()
    {
        HttpContext.Session.SetString("Name", "The Doctor"); // will not work
        HttpContext.Session.SetInt32("Age", 773);  // will not work

    }
 }

这是我的 Startup.cs:

    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddDistributedMemoryCache();

            services.AddSession(options =>
            {
                // Set a short timeout for easy testing.
                options.IdleTimeout = System.TimeSpan.FromMinutes(30);
                options.Cookie.HttpOnly = true;
            });

            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);

            // In production, the Angular files will be served from this directory
            services.AddSpaStaticFiles(configuration =>
            {
                configuration.RootPath = "ClientApp/dist";
            });

            services.Configure<ServiceSettings>(Configuration.GetSection("ServiceSettings"));
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Error");
                app.UseHsts();
            }

            app.UseSession();
            app.UseHttpsRedirection();
            app.UseStaticFiles();
            app.UseSpaStaticFiles();

            app.UseMvc(routes =>
            {
                routes.MapRoute(
                    name: "default",
                    template: "{controller}/{action=Index}/{id?}");
            });

            app.UseSpa(spa =>
            {
                // To learn more about options for serving an Angular SPA from ASP.NET Core,
                // see https://go.microsoft.com/fwlink/?linkid=864501

                spa.Options.SourcePath = "ClientApp";

                if (env.IsDevelopment())
                {
                    spa.UseAngularCliServer(npmScript: "start");
                }
            });
        }
    }

我需要在 MySession 类中注入(inject)一些东西吗？

Answer 1

您仍然可以通过 HttpContext 访问 Session。您如何必须通过 IHttpContextAccessor 访问 session ，顾名思义，这将允许访问 Controller 和其他框架类外部的 HttpContext本地成员。

首先，您需要将访问器添加到 DI 容器。

services.AddHttpContextAccessor();

API Reference

从那里你需要将它注入(inject)所需的类并访问所需的成员

public class MySession {
    IHttpContextAccessor accessor;

    public MySession(IHttpContextAccessor accessor) {
        this.accessor = accessor;
    }

    public void Foo() {
        var httpContext = accessor.HttpContext;
        httpContext.Session.SetString("Name", "The Doctor");
        httpContext.Session.SetInt32("Age", 773);
    }
}