'InvalidOperationException' error when using services.Add Wkhtmltopdf() in ASP.NET Razor project

[MateusKernDigibyte]

I put services.AddWkhtmltopdf(); in the ConfigureServices method in Startup.cs in my .NET Core project using Razor and I got this error when trying to access the login page:

InvalidOperationException: Session has not been configured for this application or request.

This one is my Startup class:

using Microsoft.AspNetCore.Builder; using Microsoft.AspNetCore.Hosting; using Microsoft.AspNetCore.Http; using Microsoft.AspNetCore.Identity; using Microsoft.AspNetCore.Identity.UI.Services; using Microsoft.EntityFrameworkCore; using Microsoft.Extensions.Configuration; using Microsoft.Extensions.DependencyInjection; using Microsoft.Extensions.Hosting; using System; using System.Threading.Tasks; using Wkhtmltopdf.NetCore;

namespace Digibyte.Controle { public class Startup { public IConfiguration Configuration { get; }

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

    // This method gets called by the runtime. Use this method to add services to the container.
    public void ConfigureServices(IServiceCollection services)
    {
        services.Configure<CookiePolicyOptions>(options =>
        {
            // This lambda determines whether user consent for non-essential cookies is needed for a given request.
            options.CheckConsentNeeded = context => true;
            options.MinimumSameSitePolicy = SameSiteMode.None;
        });

        //Repositories and Services
        ...

        //HTML to PDF Transformer, which we use to print slips
        services.AddWkhtmltopdf();

        services.AddDbContext<ApplicationDbContext>(options => options.UseLazyLoadingProxies().UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));

        services.AddIdentity<IdentityUser, IdentityRole>(options =>
        {
            options.Password.RequireNonAlphanumeric = false;
            options.Password.RequireUppercase = false;
            options.Password.RequiredLength = 6;
            options.User.RequireUniqueEmail = true;
        })
        .AddDefaultUI()
        .AddEntityFrameworkStores<ApplicationDbContext>()
        .AddDefaultTokenProviders();

        services.AddMvc();
    }

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IWebHostEnvironment env, IServiceProvider serviceProvider)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }
        else
        {
            app.UseExceptionHandler("/Home/Error");
            // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
            app.UseHsts();
        }

        app.UseCors(x => x.AllowAnyOrigin().AllowAnyHeader().AllowAnyMethod());
        app.UseHttpsRedirection();
        app.UseStaticFiles();
        app.UseCookiePolicy();
        app.UseRouting();
        app.UseAuthentication();
        app.UseAuthorization();

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

}

When I comment out the services.AddWkhtmltopdf(); no more mistakes

Can anyone help me with this error?

[MateusKernDigibyte]

I fixed it by putting services.AddWkhtmltopdf(); after services.AddMvc();, e ficou assim:

public void ConfigureServices(IServiceCollection services)
    {
        services.Configure<CookiePolicyOptions>(options =>
        {
            options.CheckConsentNeeded = context => true;
            options.MinimumSameSitePolicy = SameSiteMode.None;
        });
        services.AddDbContext<ApplicationDbContext>(options => options.UseLazyLoadingProxies().UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));

        services.AddIdentity<IdentityUser, IdentityRole>(options =>
        {
            options.Password.RequireNonAlphanumeric = false;
            options.Password.RequireUppercase = false;
            options.Password.RequiredLength = 6;
            options.User.RequireUniqueEmail = true;
        })
        .AddDefaultUI()
        .AddEntityFrameworkStores<ApplicationDbContext>()
        .AddDefaultTokenProviders();

        services.AddMvc();
        services.AddWkhtmltopdf();
    }