Problem with adding controller

Question

User887623398 posted

Hello,

When I try to add a controller to the project I encounter this error:

https://drive.google.com/open?id=1UAl4U1WPkk21Hw6YYCjwY_gafATxUVAL

here comes my startup:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Components;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.HttpsPolicy;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using SaeedTry1.Data;
using Microsoft.EntityFrameworkCore;

namespace SaeedTry1
{
    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.
        // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddRazorPages();
            services.AddServerSideBlazor();
            services.AddSingleton<WeatherForecastService>();
            services.AddDbContext<SqlDbContext>(
  options => options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));
        }

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

            app.UseRouting();

            app.UseEndpoints(endpoints =>
            {
                //    endpoints.MapControllerRoute(
                //    name: "default",
                //    pattern: "{controller}/{action}");
                endpoints.MapControllers();
               
                endpoints.MapBlazorHub();
                endpoints.MapFallbackToPage("/_Host");
            });
        }
    }
}

Please if you have any experience with this issue help me.

Thanks,

Saeed

Answer 1

User-821857111 posted

There could be a number of reasons for this. Try building the project first. If it doesn't compile, fix the code then try scaffolding again. Otherwise you may need to uninstall Microsoft.VisualStudio.Web.CodeGeneration.Design and reinstall it. Do this via the PAckage Manager Console:

uninstall-package Microsoft.VisualStudio.Web.CodeGeneration.Design
install-package Microsoft.VisualStudio.Web.CodeGeneration.Design