Why my Entity Framework Core Database-First Model Custom Changes Gone After Re-Scaffold? Any Solution

Question

I am working with ASP.Net Core 2.1 & I am facing a problem. I have been working on implementing a Database-First application. The initial Scaffold-DbContext command works just fine and creates all my entities correctly. After that, I make some changes to model files for Validation. My DBA made a new change on DB so I re-Scaffold the DB. Then I notice that re-scaffold overwrites all the custom code I have added to all the model files. Is there any way I re-scaffold the DB but that only changes those files changes by DBA in ASP.Net Core DB First Approach? Every time I am facing this problem. I Re-scaffold with the below command:

Scaffold-DbContext "Server=192.168.46.101;Database=DBNAME;User Id=USERID;Password=PASSWORD" Microsoft.EntityFrameworkCore.SqlServer -ContextDir Data -OutputDir Models -UseDatabaseNames -force

My Custom Added Annotation to Model:

    //Custom Annotation
    [Key]
    public int COLORCODE { get; set; }

    //Custom Validation
    [Required(ErrorMessage = "Color Name can not be empty")]
    public string COLOR { get; set; }

    public string REMARKS { get; set; }

After Re-scaffolding my code be like:

    public int COLORCODE { get; set; }
    public string COLOR { get; set; }
    public string REMARKS { get; set; }

My Program.cs File:

public class Program
{
    public static void Main(string[] args)
    {
        CreateWebHostBuilder(args).Build().Run();
    }

    public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
        WebHost.CreateDefaultBuilder(args)
            .ConfigureLogging((hostingContext, logging) =>
            {
                logging.AddConfiguration(hostingContext.Configuration.GetSection("Logging"));
                logging.AddConsole();
                logging.AddDebug();
                logging.AddEventSourceLogger();
                logging.AddNLog();
            })
            .UseStartup<Startup>();
}

My Startup.cs File:

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.
    public void ConfigureServices(IServiceCollection services)
    {

        services.ConfigureApplicationCookie(options =>
        {
            options.AccessDeniedPath = new PathString("/Administrator/AccessDenied");
        });

        services.Configure<CookiePolicyOptions>(options =>
        {
            // This lambda determines whether user consent for non-essential cookies is needed for a given request.
            // options.CheckConsentNeeded = context => true;
            options.MinimumSameSitePolicy = SameSiteMode.None;
        });

        services.AddDbContext<Context>(options =>
            options.UseSqlServer(
                Configuration.GetConnectionString("ConnectionName")));


        services.AddIdentity<IdentityUser, IdentityRole>(options =>
        {
            options.Password.RequiredLength = 15;
            options.Password.RequiredUniqueChars = 5;
            options.Password.RequireNonAlphanumeric = false;

            options.SignIn.RequireConfirmedEmail = true;
            options.Tokens.EmailConfirmationTokenProvider = "CustomEmailConfirmation";

            options.Lockout.MaxFailedAccessAttempts = 5;
            options.Lockout.DefaultLockoutTimeSpan = TimeSpan.FromMinutes(15);
        })
        .AddEntityFrameworkStores<Context>()
        .AddDefaultTokenProviders()
        .AddTokenProvider<CustomEmailConfirmationTokenProvider<IdentityUser>>("CustomEmailConfirmation");

        // REGISTER ExtractEMService
        ExtractEMService.ExtractEMRegisterService(services);

        //services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
        services.AddMvc(options =>
        {
            var policy = new AuthorizationPolicyBuilder()
            .RequireAuthenticatedUser()
            .Build();
            options.Filters.Add(new AuthorizeFilter(policy));

        }).SetCompatibilityVersion(CompatibilityVersion.Version_2_1);

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
            app.UseDatabaseErrorPage();
        }
        else
        {
            app.UseExceptionHandler("/Error");
            app.UseStatusCodePagesWithReExecute("/Error/{0}");

            //app.UseExceptionHandler("/Home/Error");
            app.UseHsts();
        }

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

        app.UseAuthentication();

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

score 2 · Answer 1 · answered Nov 04 '20 at 15:55

There is no way you can do that, but just leave the generated classes as is and use a buddy class for the data annotations:

[MetadataType(typeof(MetaData))]
public partial class Person
{
    public class MetaData
    {
        [Required]
        [Display(Name = "Enter Your Name")]
        public string FirstName;

      
    }
}

https://ryanhayes.net/data-annotations-for-entity-framework-4-entities-as-an-mvc-model/

Why my Entity Framework Core Database-First Model Custom Changes Gone After Re-Scaffold? Any Solution

1 Answers1