.Net Core MVC

To show error messages

->Properties: /launchSettings.json

"environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development"
      }

In AZURE

App services -> Settings -> Application settgins -> Connection string -> Add new connection string: "ASPNETCORE_ENVIRONMENT": "Development"

Authentication

https://docs.microsoft.com/en-us/aspnet/core/security/authentication/identity?tabs=visual-studio%2Caspnetcore2x

Make sure you created project with authentication setting (work or school, individual account, no authentication)

// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
    services.AddDbContext<ApplicationDbContext>(options =>
        options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));

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

    services.Configure<IdentityOptions>(options =>
    {
        // Password settings
        options.Password.RequireDigit = true;
        options.Password.RequiredLength = 8;
        options.Password.RequireNonAlphanumeric = false;
        options.Password.RequireUppercase = true;
        options.Password.RequireLowercase = false;
        options.Password.RequiredUniqueChars = 6;

        // Lockout settings
        options.Lockout.DefaultLockoutTimeSpan = TimeSpan.FromMinutes(30);
        options.Lockout.MaxFailedAccessAttempts = 10;
        options.Lockout.AllowedForNewUsers = true;

        // User settings
        options.User.RequireUniqueEmail = true;
    });

    services.ConfigureApplicationCookie(options =>
    {
        // Cookie settings
        options.Cookie.HttpOnly = true;
        options.ExpireTimeSpan = TimeSpan.FromMinutes(30);
        // If the LoginPath isn't set, ASP.NET Core defaults 
        // the path to /Account/Login.
        options.LoginPath = "/Account/Login";
        // If the AccessDeniedPath isn't set, ASP.NET Core defaults 
        // the path to /Account/AccessDenied.
        options.AccessDeniedPath = "/Account/AccessDenied";
        options.SlidingExpiration = true;
    });

    // Add application services.
    services.AddTransient<IEmailSender, EmailSender>();

    services.AddMvc();
}

When creating a new object

Model (add-> class)-> Controller(add-> Controller) -> View

Database connection string

appsettings.json

{
  "ConnectionStrings": {
    "DefaultConnection": "Server=tcp:sanbox.database.windows.net,1433;Initial Catalog=SandboxDB;Persist Security Info=False;User ID={username};Password={password};MultipleActiveResultSets=False;Encrypt=True;TrustServerCertificate=False;Connection Timeout=30;"
  },
  "Logging": {
    "IncludeScopes": false,
    "LogLevel": {
      "Default": "Warning"
    }
  }
}

Model Binding