Entity Framework: System.ArgumentException: Format of the initialization string does not conform to specification starting at index 0

Question

I want to update my migrated database on my Asp.Net Core MVC Application, but I get the following error when I try to do this:

I have already tried a few tutorials or forum posts but unfortunately it didn't work. Could someone help me please?

That's my Startup.cs:

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using Newtonsoft.Json.Serialization;
using PlaudertischSoftware.Models;
using Pomelo.EntityFrameworkCore.MySql;
using Microsoft.Extensions.Configuration;
using Microsoft.AspNetCore.HttpOverrides;
using System.Net;
using Microsoft.AspNetCore.Http;

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

        public void ConfigureServices(IServiceCollection services)
        {
            services.Configure<CookiePolicyOptions>(options =>
            {
                options.CheckConsentNeeded = context => true;
                options.MinimumSameSitePolicy = SameSiteMode.None;
            });
            services.AddRazorPages();
            services.AddMvc()
                .SetCompatibilityVersion(CompatibilityVersion.Version_3_0);
            services.AddMvc(option => option.EnableEndpointRouting = false);
            services.AddDbContext<DatenbankKontext>(options =>
            options.UseSqlServer(Configuration.GetConnectionString("MyConnectionString")));
            services.AddControllersWithViews()
                .AddJsonOptions(options =>
                {
            options.JsonSerializerOptions.PropertyNamingPolicy = null;
                });
            services.Configure<ForwardedHeadersOptions>(options =>
            {
                options.KnownProxies.Add(IPAddress.Parse("0.0.0.0"));
            });

        }
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.UseStaticFiles();
            app.UseCookiePolicy();

            app.UseMvc(routes =>
            {
                routes.MapRoute(
                    name: "default",
                    template: "{controller=Home}/{action=Index}/{id?}");
            });
            app.UseForwardedHeaders(new ForwardedHeadersOptions
            {
                ForwardedHeaders = ForwardedHeaders.XForwardedFor | ForwardedHeaders.XForwardedProto
            });

            app.UseAuthentication();
        }
    }
}

Here's my Program.cs:

using Microsoft.AspNetCore;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Server.HttpSys;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;
using PlaudertischSoftware.Models;
using System.IO;

namespace PlaudertischSoftware
{
    public class Program
    {
        public static void Main(string[] args)
        {
            var host = new WebHostBuilder()
               .UseKestrel()
               .UseUrls("http://*:5000")
               .UseContentRoot(Directory.GetCurrentDirectory())
               .UseIISIntegration()
               .UseStartup<Startup>()
               .Build();

            host.Run();
        }
    }
}

My ContextFactory:

using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Design;
using Microsoft.EntityFrameworkCore.Infrastructure;
using PlaudertischSoftware.Models;

namespace PlaudertischSoftware
{
    public class DatenbankKontextFactory : IDesignTimeDbContextFactory<DatenbankKontext>
    {
        public DatenbankKontext CreateDbContext(string[] args)
        {
            var optionsBuilder = new DbContextOptionsBuilder<DatenbankKontext>();
            optionsBuilder.UseSqlServer("MyConnectionString");

            return new DatenbankKontext(optionsBuilder.Options);
        }
    }
}

That's my appsettings.json:

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft": "Warning",
      "Microsoft.Hosting.Lifetime": "Information"
    }
  },
  "AllowedHosts": "*",
  "ConnectionStrings": {
    "MyConnectionString": "Server=(localdb)\\mssqllocaldb;Database=MyConnectionString;Integrated Security=True"
  }
}

But I don't have a .mdf File. In my Application the Controller creates a database and updates it dynamically — OEZ BRO
– OEZ BRO, Commented Mar 30, 2020 at 13:13

Caius Jard · Accepted Answer · 2020-03-30 16:19:03Z

1

I think the problem is here:

    public DatenbankKontext CreateDbContext(string[] args)
    {
        var optionsBuilder = new DbContextOptionsBuilder<DatenbankKontext>();

        optionsBuilder.UseSqlServer("MyConnectionString");
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

        return new DatenbankKontext(optionsBuilder.Options);
    }

That UseSqlServer is expecting an actual connection string, and you're passing it a string of "MyConnectionString" which is only the name you've called your connection string config entry, but UseSqlServer won't take it and go rummaging in your appsettings.connectionstrings looking for something with that name; it'll just take it as if it were a connection string and try to use it

I would have expected it to look more like your other line (in the services registration) which is:

optionsBuilder.UseSqlServer(Configuration.GetConnectionString("MyConnectionString"));

Actually, I'm not even really sure what your DatenbankKontextFactory is hoping to do that the DbContext creator you've already registered with DI isn't doing? If you want a DbContext for some reason and the one provided for you by DI is no good (wrong scope?) then you can ask DI to make you another one, perhaps with a different scope

edited Mar 30, 2020 at 16:19

answered Mar 30, 2020 at 16:06

Caius Jard

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1 Comment

OEZ BRO Over a year ago

Oh yes you're right. The DatenbankKontextFactory is completely useless. I already have a dbcontext. I had that from some confusing internet tutorials

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