Get Browser Info,Os Info and Device Type

public void ConfigureServices(IServiceCollection services)
{
// Add browser detection services.
    services.AddDetection()
                 .AddDevice();
.AddBrowser()   // concept
.AddEngine()    // concept
.AddPlatform(); // concept

    // Add framework services.
    services.AddMvc();
}

public class HomeController : Controller
{    
    private readonly IUserAgent _useragent;    
    private readonly IBrowser _browser;
    private readonly IEngine _engine;
    private readonly IPlatform _platform;
private readonly IUserAgent _useragent;
    private readonly IDevice _device; 

    public HomeController(IBrowserResolver browserResolver, 
        IEngineResolver engineResolver, IDeviceResolver deviceResolver,
        IPlatformResolver platformResolver)
    {
        _useragent = browserResolver.UserAgent,        
        _browser = browserResolver.Browser,
        _engine = engineResolver.Engine,
        _platform = platformResolver.Platform
        _useragent = deviceResolver.UserAgent,
        _device = deviceResolver.Device
    }

    public IActionResult Index()
    {            
        return View();
    }
}

public async Task<Store> FindClosestStore(DbGeography location)
{
    using (var context = new StoreContext())
    {
        return await (from s in context.Stores
            orderby s.Location.Distance(location)
            select s).FirstAsync();
    }
}

Microsoft.AspNetCore.Mvc.Core
Microsoft.AspNetCore.Mvc.Cors
Microsoft.AspNetCore.Mvc.Formatters.Json

namespace AspNetCoreWebAPIOnly 
{ 
    public class Startup 
    { 
        public void ConfigureServices(IServiceCollection services) 
        { 
            var mvcCoreBuilder = services.AddMvcCore(); 
            mvcCoreBuilder 
                .AddFormatterMappings() 
                .AddJsonFormatters() 
                .AddCors(); 
        } 

        public void Configure(IApplicationBuilder app, IHostingEnvironment env) 
        { 
            app.UseMvc(); 
        } 
    } 
}

namespace AspNetCoreWebAPIOnly.Controllers 
{ 
    [Route("api/[controller]")] 
    // ControllerBase instead of Controller 
    public class ValuesController : ControllerBase 
    { 
        // GET api/values 
        [HttpGet] 
        public IEnumerable<string> Get() 
        { 
            return new[] { "value1", "value2" }; 
        } 
    } 
}

• expand$: بصورت نرمال، هنگام کوئری گرفتن از یک کالکشن OData، پاسخ سرور موجودیت‌های مرتبط (related entities) را شامل نمی‌شود. با استفاده از expand$ می‌توانیم موجودیت‌های مرتبط را بصورت inline در پاسخ سرور دریافت کنیم.
• select$: از این متد برای انتخاب چند خاصیت بخصوص از پاسخ سرور استفاده می‌شود، بجای آنکه تمام خاصیت‌ها بارگذاری شوند.
• value$: با این متد مقدار خام (raw) فیلد‌ها را بدست می‌آورید، بجای دریافت آنها در فرمت OData.

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Endpoint xyz contains authorization metadata, but a middleware was not found that supports authorization.
Configure your application startup by adding app.UseAuthorization() inside the call to Configure(..) in the application startup code.

public void Configure(IApplicationBuilder app)
{
    ...

    app.UseRouting();

    app.UseAuthentication();
    app.UseAuthorization();

    app.UseEndpoints(endpoints =>
    {
        endpoints.MapDefaultControllerRoute();
    });
}

public class HomeController : ControllerBase
{
    [Authorize]
    public IActionResult BuyWidgets()
    {
        ...
    }
}

public void Configure(IApplicationBuilder app)
{
    ...

    app.UseRouting();

    app.UseAuthentication();
    app.UseAuthorization();

    app.UseEndpoints(endpoints =>
    {
        endpoints.MapDefaultControllerRoute().RequireAuthorization();
    });
}

[AllowAnonymous]
public class HomeController : ControllerBase
{
    ...
}

public void ConfigureServices(IServiceCollection services)
{
    ...
    
    services.AddAuthorization(options =>
    {
        options.DefaultPolicy = new AuthorizationPolicyBuilder()
          .RequireAuthenticatedUser()
          .RequireScope("MyScope")
          .Build();
    });
}

public void ConfigureServices(IServiceCollection services)
{
    services.AddAuthorization(options =>
    {
        options.FallbackPolicy = new AuthorizationPolicyBuilder()
          .RequireAuthenticatedUser()
          .RequireScope("MyScope")
          .Build();
    });
}

public void Configure(IApplicationBuilder app)
{
    app.UseRouting();

    app.UseAuthentication();
    app.UseAuthorization();

    app.UseEndpoints(endpoints =>
    {
        endpoints.MapDefaultControllerRoute();
    });
}

[AllowAnonymous]
public class HomeController : ControllerBase
{
}

public void Configure(IApplicationBuilder app)
{
    ...

    app.UseRouting();

    app.UseAuthentication();
    app.UseAuthorization();

    app.UseEndpoints(endpoints =>
    {
        endpoints
            .MapHealthChecks("/healthz")
            .RequireAuthorization(new AuthorizeAttribute(){ Roles = "admin", });
    });
}

 // does not work: services.AddScoped<IGenericRepository<T>,EFRepository<T>>();

public void ConfigureServices(IServiceCollection services)
{
    services.AddScoped<IStore<User>, SqlStore<User>>();
    services.AddScoped<IStore<Invoice>, SqlStore<Invoice>>();
    services.AddScoped<IStore<Payment>, SqlStore<Payment>>();
    // ...
}

public void ConfigureServices(IServiceCollection services)
{
    services.AddScoped(typeof(IStore<>), typeof(SqlStore<>));
}

services.Scan(scan => scan 
  .FromAssemblyOf<CombinedService>()  
    .AddClasses(x=> x.AssignableTo(typeof(IOpenGeneric<>))) // Can close generic types 
    .AsMatchingInterface())

services.AddTransient<IOrderHandler, OrderHandlerLazy>();
services.AddTransient<IAccounting, Accounting>()
            .AddTransient(serviceProvider => new Lazy<IAccounting>(() => serviceProvider.GetRequiredService<IAccounting>()));
services.AddTransient<ISales, Sales>()
           .AddTransient(serviceProvider => new Lazy<ISales>(() => serviceProvider.GetRequiredService<ISales>()));

services.AddTransient(typeof(Lazy<>), typeof(LazyFactory<>));

public class LazyFactory<T> : Lazy<T> where T : class
{
    public LazyFactory(IServiceProvider provider)
        : base(() => provider.GetRequiredService<T>())
    {
    }
}

 public class Category
    {
        public int Id { get; set; }

        public string Title { get; set; }
    }

 public class CategoryMap : EntityTypeConfiguration<Entity.Category>
    {
        public CategoryMap()
        {
            ToTable( "Category" );

            HasKey( _field => _field.Id );

            Property( _field => _field.Title )
            .IsRequired();            
        }
    }

using System.Data.Entity;
using System.Data.Entity.Infrastructure;

namespace DataAccess
{
    public interface IUnitOfWork
    {
        DbSet<TEntity> Set<TEntity>() where TEntity : class;
        DbEntityEntry<TEntity> Entry<TEntity>() where TEntity : class;
        void SaveChanges();     
        void Dispose();
    }
}

[InheritedExport( typeof( IUnitOfWork ) )]
    public class DatabaseContext : DbContext, IUnitOfWork
    {
        private DbTransaction transaction = null;

        public DatabaseContext()           
        {
            this.Configuration.AutoDetectChangesEnabled = false;
            this.Configuration.LazyLoadingEnabled = true;
        }

        protected override void OnModelCreating( DbModelBuilder modelBuilder )
        {
            modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();

            modelBuilder.AddFormAssembly( Assembly.GetAssembly( typeof( Entity.Map.CategoryMap ) ) );
        }

        public DbEntityEntry<TEntity> Entry<TEntity>() where TEntity : class
        {
            return this.Entry<TEntity>();
        }      
    }

 public static class ModelBuilderExtension
    {
        public static void AddFormAssembly( this DbModelBuilder modelBuilder, Assembly assembly )
        {
            Array.ForEach<Type>( assembly.GetTypes().Where( type => type.BaseType != null && type.BaseType.IsGenericType && type.BaseType.GetGenericTypeDefinition() == typeof( EntityTypeConfiguration<> ) ).ToArray(), delegate( Type type )
            {
                dynamic instance = Activator.CreateInstance( type );
                modelBuilder.Configurations.Add( instance );
            } );
        }
    }

public class BusinessBase<TEntity> where TEntity : class
    {        
        public BusinessBase( IUnitOfWork unitOfWork )
        {
            this.UnitOfWork = unitOfWork;
        }

        [Import]
        public IUnitOfWork UnitOfWork
        {
            get;
            private set;
        }

        public virtual IEnumerable<TEntity> GetAll()
        {
            return UnitOfWork.Set<TEntity>().AsNoTracking();
        }

        public virtual void Add( TEntity entity )
        {
            try
            {             
                UnitOfWork.Set<TEntity>().Add( entity );
                UnitOfWork.SaveChanges();
            }
            catch
            {              
                throw;
            }
            finally
            {
                UnitOfWork.Dispose();
            }
        }
    }

 public class Category : BusinessBase<Entity.Category>
    {      
        [ImportingConstructor]
        public Category( [Import( typeof( IUnitOfWork ) )] IUnitOfWork unitOfWork )
            : base( unitOfWork )
        {
        }
    }

public class Plugin
    {        
        public void Run()
        {
            AggregateCatalog catalog = new AggregateCatalog();

            Container = new CompositionContainer( catalog );

            CompositionBatch batch = new CompositionBatch();

            catalog.Catalogs.Add( new AssemblyCatalog( Assembly.GetExecutingAssembly() ) );

            batch.AddPart( this );

            Container.Compose( batch );
        }

        public CompositionContainer Container 
        {
            get; 
            private set;
        }
    }

  class Program
    {
        static void Main( string[] args )
        {
            Plugin plugin = new Plugin();
            plugin.Run();

            Category category = new Category(plugin.Container.GetExportedValue<IUnitOfWork>());
            category.GetAll().ToList().ForEach( _record => Console.Write( _record.Title ) );
        }
    }

برای درک بهتر موضوع به ساختار کلاس‌های اعتبارسنجی در تصویر بعدی دقت کنید.

• اعتبار سنجی در چه قسمت هایی اتفاق می‌افتد:

1.Property   

2.Entity   

3.Context

        [Required(ErrorMessage = "لطفا نام نویسنده را مشخص نمائید")]
        public string AuthorName { set; get; }

        [StringLength(100,MinimumLength=3,ErrorMessage="حداقل سه حرف و حداکثر 100 حرف وارد نمایید.")]
        public string AuthorName { set; get; }

Validation Attributes
AssemblySystem.ComponentModel.DataAnnotations.dll
NamespaceSystem.ComponentModel.DataAnnotations
StringLength
RegularExpression
DataType
Required
Range
CustomValidation

Mapping Attributes
AssemblyEntityFramework.dll
NamespaceSystem.ComponentModel.DataAnnotations
Key
Column,Table
ComplexType
ConCurrency
TimeStamp
DatabaseGenerated
ForeignKey
InverseProperty
MaxLength
MinLength
NotMapped

public class Blog : IValidatableObject
    {
       
        public int blogID { set; get; }

        [Required(ErrorMessage = "لطفا عنوان وبلاگ را مشخص نمائید")]
        public string Title { set; get; }
        [Required(ErrorMessage = "لطفا نام نویسنده را مشخص نمائید")]
        [StringLength(100,MinimumLength=3,ErrorMessage="حداقل سه حرف و حداکثر 100 حرف وارد نمایید.")]
        public string AuthorName { set; get; }
    

        public IEnumerable<ValidationResult> Validate(ValidationContext ValidationContext)
        {
             if (this.AuthorName =="بدون نام")
                yield return new ValidationResult
                    ("این نام برای نام نویسنده مجاز نمی‌باشد.", new[] { "AuthorName"});

            if (this.AuthorName == this.Title)
                yield return new ValidationResult
                    (" نام نویسنده وبلاگ و عنوان وبلاگ نمی‌تواند همسان باشد.!", new[] { "AuthorName", "Title" });
        }
    }

  protected override DbEntityValidationResult ValidateEntity(DbEntityEntry entityEntry, System.Collections.Generic.IDictionary<object, object> items)
        {
            return base.ValidateEntity(entityEntry, items);
        }

// اعتبار سنجی یک خاصیت
ICollection<DbValidationError> ValidationProperty = Context.Entry(Blog).Property(p => p.AuthorName).GetValidationErrors();

// اعتبار سنجی یک موجودیت
DbEntityValidationResult ValidationEntity = Context.Entry(Blog).GetValidationResult();

// اعتبار سنجی همه موجودیت‌ها
 IEnumerable<DbEntityValidationResult> ValidationContext = Context.GetValidationErrors();

EntityState.Added ||  EntityState.Modified