asp.net core and EF core error while add migration

Question

In a asp.net core app, I am trying to to migration for EF code fist.

I got below errors,

An error occurred while calling method 'ConfigureServices' on startup class 'WebAppHandOn.Startup'. Consider using IDbContextFactory to override the initialization of the DbContext at design-time. Error: Could not load file or assembly 'Microsoft.AspNetCore.Routing, Version=1.0.1.0, Culture=neutral, PublicKeyToken=adb9793829ddae60' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

No parameterless constructor was found on 'ApplicationDbContext'. Either add a parameterless constructor to 'ApplicationDbContext' or add an implementation of 'IDbContextFactory' in the same assembly as 'ApplicationDbContext'.

Here are the different code files,

1. Startup Class

   public void ConfigureServices(IServiceCollection services)
   {
       // Add framework services.
       services.AddMvc();
   
       // Add EntityFramework's Identity support.
       services.AddEntityFramework();
   
       // Add ApplicationDbContext.
       services.AddDbContext<ApplicationDbContext>(options => options.UseSqlServer(Configuration["Data:DefaultConnection:ConnectionString"]));
   }
   

2. ApplicationDBContext Class

   public class ApplicationDbContext : DbContext {
       #region Constructor
   
       public ApplicationDbContext(DbContextOptions options) : base(options)
       {
       }
       #endregion Constructor
   
       #region Methods
       protected override void OnModelCreating(ModelBuilder modelBuilder)
       {
           base.OnModelCreating(modelBuilder);
       }
       #endregion Methods
   
       #region Properties
       public DbSet<Item> Items { get; set; }
       public DbSet<Comment> Comments { get; set; }
       public DbSet<ApplicationUser> Users { get; set; }
       #endregion Properties
   }
   

3. Project.json Class

 {
      "dependencies": {
     "Microsoft.AspNetCore.Mvc": "1.0.0",
    "Microsoft.AspNetCore.Server.IISIntegration": "1.0.0",
    "Microsoft.AspNetCore.Server.Kestrel": "1.0.0",
    "Microsoft.Extensions.Configuration.EnvironmentVariables": "1.0.0",
    "Microsoft.Extensions.Configuration.FileExtensions": "1.0.0",
    "Microsoft.Extensions.Configuration.Json": "1.0.0",
    "Microsoft.Extensions.Logging": "1.0.0",
    "Microsoft.Extensions.Logging.Console": "1.0.0",
    "Microsoft.Extensions.Logging.Debug": "1.0.0",
    "Microsoft.Extensions.Options.ConfigurationExtensions": "1.0.0",
    "Microsoft.AspNetCore.Diagnostics": "1.0.0",
    "Microsoft.AspNetCore.Routing": "1.0.0",
    "Microsoft.AspNetCore.Authentication.JwtBearer": "1.0.0",
    "Microsoft.AspNetCore.StaticFiles": "1.0.0",
    "Microsoft.VisualStudio.Web.BrowserLink.Loader": "14.0.0",
    "Newtonsoft.Json": "9.0.1",
    "Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore": "1.0.0",
    "Microsoft.AspNetCore.Identity.EntityFrameworkCore": "1.0.0",
    "Microsoft.EntityFrameworkCore": "1.0.0",
    "Microsoft.EntityFrameworkCore.SqlServer": "1.0.0",
    "Microsoft.EntityFrameworkCore.Design": "1.0.0-preview2-final",
    "TinyMapper": "2.0.8"
  },

  "tools": {
    "Microsoft.AspNetCore.Server.IISIntegration.Tools": "1.0.0-preview2-final",
    "Microsoft.EntityFrameworkCore.Tools": "1.0.0-preview2-final"
  },

Answer 1

Check yourproject.csproj file, remove any preview version in any PackageReference tag and reinstall stable version with manage NuGet packages. Hope that helps