Asp Net Core: Connection to existing SqlServer

Question

I am trying to connect my asp net core application with my database created with Microsoft Sql Server Management but at my first migration i get this error:

System.ArgumentException: Format of the initialization string does not conform to specification starting at index 0.
   at System.Data.Common.DbConnectionOptions.GetKeyValuePair(String connectionString, Int32 currentPosition, StringBuilder buffer, String& keyname, String& keyvalue)
   at System.Data.Common.DbConnectionOptions.ParseInternal(Dictionary`2 parsetable, String connectionString, Boolean buildChain, Dictionary`2 synonyms)
   at System.Data.Common.DbConnectionOptions..ctor(String connectionString, Dictionary`2 synonyms)
   at System.Data.SqlClient.SqlConnectionString..ctor(String connectionString)
   at System.Data.SqlClient.SqlConnectionFactory.CreateConnectionOptions(String connectionString, DbConnectionOptions previous)
   at System.Data.ProviderBase.DbConnectionFactory.GetConnectionPoolGroup(DbConnectionPoolKey key, DbConnectionPoolGroupOptions poolOptions, DbConnectionOptions& userConnectionOptions)
   at System.Data.SqlClient.SqlConnection.ConnectionString_Set(DbConnectionPoolKey key)
   at System.Data.SqlClient.SqlConnection.set_ConnectionString(String value)
   at Microsoft.EntityFrameworkCore.Storage.Internal.SqlServerConnection.CreateDbConnection()
   at Microsoft.EntityFrameworkCore.Internal.LazyRef`1.get_Value()
   at Microsoft.EntityFrameworkCore.Migrations.Internal.Migrator.Migrate(String targetMigration)
   at Microsoft.EntityFrameworkCore.Design.Internal.MigrationsOperations.UpdateDatabase(String targetMigration, String contextType)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.UpdateDatabase.<>c__DisplayClass0_1.<.ctor>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action)
Format of the initialization string does not conform to specification starting at index 0.

I don't know what i am doing wrong so if someone can help me.

Here is my connection string:

"Data": {
    "DefaultConnection": {
      "ConnectionString": "Data Source=..\\SQLSERVER;Initial Catalog=dbfichetips;Integrated Security=True;"
    }

And my Startup.cs

public class Startup
{
    public Startup(IHostingEnvironment env)
    {
        var builder = new ConfigurationBuilder()
            .SetBasePath(env.ContentRootPath)
            .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
            .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
            .AddEnvironmentVariables().Build();
    }


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

        services.AddDbContext<ApplicationDbContext>(
            options => options.UseSqlServer("Data:DefaultConnection:ConnectionString"));

        services.AddIdentity<ApplicationUser, ApplicationRole>()
            .AddEntityFrameworkStores<ApplicationDbContext, int>()
            .AddDefaultTokenProviders();

        services.Configure<IdentityOptions>(options =>
        {
            //Password settings
            options.Password.RequireDigit = false;
            options.Password.RequiredLength = 6;
            options.Password.RequireLowercase = false;
            options.Password.RequireNonAlphanumeric = false;
            options.Password.RequireUppercase = false;
        });

    }

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory, ApplicationDbContext applicationDbContext)
    {
        loggerFactory.AddConsole();
        loggerFactory.AddDebug();

        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
            app.UseBrowserLink();
            applicationDbContext.Database.Migrate();
        }
        else
        {
            app.UseExceptionHandler("/Home/Error");
        }

        app.UseIdentity();
        app.UseStaticFiles();

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

Answer 1

UseSqlServer expects "real" connection string, not keyname in configuration.

Instead of

services.AddDbContext<ApplicationDbContext>(
        options => options.UseSqlServer("Data:DefaultConnection:ConnectionString"));

you need

services.AddDbContext<ApplicationDbContext>(
        options => options.UseSqlServer(builder["Data:DefaultConnection:ConnectionString"]));

And save builder in variable/property - currently it's garbage collected after Startup constructor is done.