(The God Class Problem (Behavioral Form 

یکی از مخاطراتی که ممکن است موجب عدم بروز مزایای شیء گرایی در طرح شما شود، بحث God Class می‌باشد. شکل رفتاری آن (Behavioral Form) بیشتر در اثر یک خطای مشترک بین توسعه دهندگان پارادایم action-oriented و در جریان مهاجرت به سمت پارادایم شیء گرا، رخ می‌دهد.

مراقب کلاس هایی باشید که تعداد خیلی زیادی رفتار نامرتبط دارند؛ یعنی رفتارهایی که فقط برروی زیر مجموعه ای از داده‌های کلاس کار می‌کنند. God Class‌ها اغلب دارای اینگونه رفتارهای نامرتبط به هم هستند. (Beware of classes that have too much noncommunicating behavior, that is, methods that operate on a proper subset of the data members of a class. God classes often exhibit much noncommunicating behavior)

راه حل‌های پیشنهادی برای مشکل مطرح شده به شکل زیر می‌باشند:

با توجه به طراحی شکل بالا، یا خود کلاس CourseOffering با استفاده از لیست دوره‌های گذرانده شده توسط دانشجو و لیست دوره‌های پیش نیاز دوره انتخابی، چک کردن را انجام دهد و یا کلاسی با عنوان PrereqChecker که یک Controller Class (کلاسی که فقط رفتار دارد و داده مورد نظر خود را توسط سایر کلاس‌ها و از طریق accessor methodهای آنها تأمین می‌کند) می‌باشد، وظیفه چک کردن را برعهده بگیرد.

علاوه بر اینکهaccessor method ها، داده را برای کلاس‌های کنترلر مهیا می‌کنند (مانند مثال بالا)، وظیفه‌ی مهیا کردن داده برای UI (رابط کاربری) را نیاز بر عهده خواهند داشت. به این صورت که رابط کاربری، با استفاده از این متدها، مشخصات درونی مدل را نمایش دهد و یا این امکان را به کاربر می‌دهد که این مشخصات درونی مدل را ویرایش کرده و به سمت مدل ارسال نماید.

قاعده شهودی 3.5

در برنامه‌هایی که شامل یک مدل شی گرایی می‌باشند که با رابط کاربری تعامل دارند، مدل نباید به رابط کاربری وابسته باشد. رابط کاربری می‌بایست وابسته به مدل باشد. (In applications that consist of an object-oriented model interacting with a user interface, the model should never be dependent on the interface. The interface should be dependent on the model)

برای عدم نقض این قاعده شهودی، لازم است در مدل یکسری accessor method در نظر گرفته شود تا رابط کاربری از آن استفاده کند؛ ولی باید مراقب بود که این accessor method‌ها صرفا توسط رابط کاربری استفاده شود و عدم توجه به این قضیه، احتمالا شما را به سمت نقض قاعده 3.3 متمایل خواهد کرد.

My goal here is to walk through my process of building react from the groundup, hopefully giving you an intuition to why things behave the way they do in react.

EntityFramework.Exceptions simplifies this by handling all the database specific details and throwing different exceptions. All you have to do is inherit your DbContext from ExceptionProcessorContext and handle the exception(s) such as UniqueConstraintException, CannotInsertNullException, MaxLengthExceededException, NumericOverflowException you need. 

function ScopeTest() {
    if (true) {
        var foo = 'use anywhere';
        let bar = 'use in this block';
    }
    console.log(foo); // works!
    console.log(bar); // error!
}

let isDone: boolean = false;

let decimal: number = 6;
let hex: number = 0xf00d;
let binary: number = 0b1010;
let octal: number = 0o744;

let name: string = "bob";
name = 'smith';

let list: number[] = [1, 2, 3];

enum Color {Red, Green, Blue};
let c: Color = Color.Green;

let notSure: any = 4;
notSure = "maybe a string instead";
notSure = false; // okay, definitely a boolean

 function warnUser(): void {
        alert("This is my warning message");
}

let myString= 'this is a string';
myString= 42; // error!

function ReturnNumber() {
   return 42;
}
let anotherString = 'this is also a string';
anotherString = ReturnNumber(); // error!

 enum Category { Biography, Poetry, Fiction }; // 0, 1, 2

 enum Category { Biography = 1, Poetry, Fiction }; // 1, 2, 3

 enum Category{ Biography = 5, Poetry = 8, Fiction = 9 }; // 5, 8, 9

 let favoriteCategory: Category = Category.Biography;

 console.log(favoriteCategory); // 5

let categoryString= Category[favoriteCategory]; // Biography

let strArray1: string[] = ['here', 'are', 'strings'];

let strArray2: Array<string> = ['more', 'strings', 'here'];

let anyArray: any[] = [42, true, 'banana'];

 let myTuple: [number, string] = [25, 'truck'];

 let firstElement= myTuple[0]; // 25
let secondElement= myTuple[1]; // truck

 // other elements can have numbers or strings
myTuple[2] = 100;
myTuple[2] = 'this works!';

 let someValue: any = "this is a string";
let strLength: number = (<string>someValue).length;

 let someValue: any = "this is a string";
let strLength: number = (someValue as string).length;

Those of you who worked with ASP.NET web forms will recollect that certain server controls such as DropDownList have a property called AutoPostBack. This property when set to true automatically submits the form to the server whenever the selection changes and raises some server side event. In modern web development people prefer to use Ajax over AutoPostBack but at times AutoPostBack is what you might need. To that end this article shows how AutoPostBack can be implemented in ASP.NET Core applications. 

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Entity;
using System.Data.Objects;
using System.Diagnostics;
using System.Linq;
using System.Web;
using System.Web.Caching;

namespace EfSecondLevelCaching.Core
{
    public static class EfHttpRuntimeCacheProvider
    {
        #region Methods (6)

        // Public Methods (2) 

        public static IList<TEntity> ToCacheableList<TEntity>(
                            this IQueryable<TEntity> query,
                            int durationMinutes = 15,
                            CacheItemPriority priority = CacheItemPriority.Normal)
        {
            return query.Cacheable(x => x.ToList(), durationMinutes, priority);
        }

        /// <summary>
        /// Returns the result of the query; if possible from the cache, otherwise
        /// the query is materialized and the result cached before being returned.
        /// The cache entry has a one minute sliding expiration with normal priority.
        /// </summary>
        public static TResult Cacheable<TEntity, TResult>(
                            this IQueryable<TEntity> query,
                            Func<IQueryable<TEntity>, TResult> materializer,
                            int durationMinutes = 15,
                            CacheItemPriority priority = CacheItemPriority.Normal)
        {
            // Gets a cache key for a query.
            var queryCacheKey = query.GetCacheKey();

            // The name of the cache key used to clear the cache. All cached items depend on this key.
            var rootCacheKey = typeof(TEntity).FullName;

            // Try to get the query result from the cache.
            printAllCachedKeys();
            var result = HttpRuntime.Cache.Get(queryCacheKey);
            if (result != null)
            {
                debugWriteLine("Fetching object '{0}__{1}' from the cache.", rootCacheKey, queryCacheKey);
                return (TResult)result;
            }

            // Materialize the query.
            result = materializer(query);

            // Adding new data.
            debugWriteLine("Adding new data: queryKey={0}, dependencyKey={1}", queryCacheKey, rootCacheKey);
            storeRootCacheKey(rootCacheKey);
            HttpRuntime.Cache.Insert(
                    key: queryCacheKey,
                    value: result,
                    dependencies: new CacheDependency(null, new[] { rootCacheKey }),
                    absoluteExpiration: DateTime.Now.AddMinutes(durationMinutes),
                    slidingExpiration: Cache.NoSlidingExpiration,
                    priority: priority,
                    onRemoveCallback: null);

            return (TResult)result;
        }

        /// <summary>
        /// Call this method in `public override int SaveChanges()` of your DbContext class 
        /// to Invalidate Second Level Cache automatically.
        /// </summary>        
        public static void InvalidateSecondLevelCache(this DbContext ctx)
        {
            var changedEntityNames = ctx.ChangeTracker
                                      .Entries()
                                      .Where(x => x.State == EntityState.Added ||
                                                  x.State == EntityState.Modified ||
                                                  x.State == EntityState.Deleted)
                                      .Select(x => ObjectContext.GetObjectType(x.Entity.GetType()).FullName)
                                      .Distinct()
                                      .ToList();

            if (!changedEntityNames.Any()) return;

            printAllCachedKeys();
            foreach (var item in changedEntityNames)
            {
                item.removeEntityCache();
            }
            printAllCachedKeys();
        }
        // Private Methods (4) 

        private static void debugWriteLine(string format, params object[] args)
        {
            if (!Debugger.IsAttached) return;
            Debug.WriteLine(format, args);
        }

        private static void printAllCachedKeys()
        {
            if (!Debugger.IsAttached) return;
            debugWriteLine("Available cached keys list:");
            int count = 0;
            var enumerator = HttpRuntime.Cache.GetEnumerator();
            while (enumerator.MoveNext())
            {
                if (enumerator.Key.ToString().StartsWith("__")) continue; // such as __System.Web.WebPages.Deployment
                debugWriteLine("queryKey: {0}", enumerator.Key.ToString());
                count++;
            }
            debugWriteLine("count: {0}", count);
        }

        private static void removeEntityCache(this string rootCacheKey)
        {
            if (string.IsNullOrWhiteSpace(rootCacheKey)) return;
            debugWriteLine("Removing items with dependencyKey={0}", rootCacheKey);
            // Removes all cached items depend on this key.
            HttpRuntime.Cache.Remove(rootCacheKey);
        }

        private static void storeRootCacheKey(string rootCacheKey)
        {
            // The cacheKeys of a cacheDependency that are not already in cache ARE NOT inserted into the cache 
            // on the Insert of the item in which the dependency is used.
            if (HttpRuntime.Cache.Get(rootCacheKey) != null)
                return;

            HttpRuntime.Cache.Add(
                rootCacheKey,
                rootCacheKey,
                null,
                Cache.NoAbsoluteExpiration,
                Cache.NoSlidingExpiration,
                CacheItemPriority.Default,
                null);
        }

        #endregion Methods
    }
}

var data = context.Products.AsQueryable().Cacheable(x => x.FirstOrDefault());

using System.Data.Entity;
using EfSecondLevelCaching.Core;
using EfSecondLevelCaching.Test.Models;

namespace EfSecondLevelCaching.Test.DataLayer
{
    public class ProductContext : DbContext
    {
        public DbSet<Product> Products { get; set; }

        public override int SaveChanges()
        {
            this.InvalidateSecondLevelCache();
            return base.SaveChanges();
        }        
    }
}

using System.Data.Entity;
using System.Linq;
using EfSecondLevelCaching.Core;
using EfSecondLevelCaching.Test.DataLayer;
using EfSecondLevelCaching.Test.Models;
using System;

namespace EfSecondLevelCaching
{
    public static class TestUsages
    {
        public static void RunQueries()
        {
            using (ProductContext context = new ProductContext())
            {
                var isActive = true;
                var name = "Product1";

                // reading from db
                var list1 = context.Products
                                   .OrderBy(one => one.ProductNumber)
                                   .Where(x => x.IsActive == isActive && x.ProductName == name)
                                   .ToCacheableList();

                // reading from cache
                var list2 = context.Products
                                   .OrderBy(one => one.ProductNumber)
                                   .Where(x => x.IsActive == isActive && x.ProductName == name)
                                   .ToCacheableList();

                // reading from cache
                var list3 = context.Products
                                   .OrderBy(one => one.ProductNumber)
                                   .Where(x => x.IsActive == isActive && x.ProductName == name)
                                   .ToCacheableList();

                // reading from db
                var list4 = context.Products
                                   .OrderBy(one => one.ProductNumber)
                                   .Where(x => x.IsActive == isActive && x.ProductName == "Product2")
                                   .ToCacheableList();
            }

            // removes products cache
            using (ProductContext context = new ProductContext())
            {
                var p = new Product()
                {
                    IsActive = false,
                    ProductName = "P4",
                    ProductNumber = "004"
                };
                context.Products.Add(p);
                context.SaveChanges();
            }

            using (ProductContext context = new ProductContext())
            {
                var data = context.Products.AsQueryable().Cacheable(x => x.FirstOrDefault());
                var data2 = context.Products.AsQueryable().Cacheable(x => x.FirstOrDefault());
                context.SaveChanges();
            }
        }
    }
}

Adding new data: queryKey=72AF5DA1BA9B91E24DCCF83E88AD1C5F, dependencyKey=EfSecondLevelCaching.Test.Models.Product

Available cached keys list:
queryKey: EfSecondLevelCaching.Test.Models.Product
queryKey: 72AF5DA1BA9B91E24DCCF83E88AD1C5F
count: 2

Fetching object 'EfSecondLevelCaching.Test.Models.Product__72AF5DA1BA9B91E24DCCF83E88AD1C5F' from the cache.

Available cached keys list:
queryKey: EfSecondLevelCaching.Test.Models.Product
queryKey: 72AF5DA1BA9B91E24DCCF83E88AD1C5F
count: 2

Fetching object 'EfSecondLevelCaching.Test.Models.Product__72AF5DA1BA9B91E24DCCF83E88AD1C5F' from the cache.

Available cached keys list:
queryKey: EfSecondLevelCaching.Test.Models.Product
queryKey: 72AF5DA1BA9B91E24DCCF83E88AD1C5F
count: 2

Adding new data: queryKey=11A2C33F9AD7821A0A31003BFF1DF886, dependencyKey=EfSecondLevelCaching.Test.Models.Product

Available cached keys list:
queryKey: 72AF5DA1BA9B91E24DCCF83E88AD1C5F
queryKey: 11A2C33F9AD7821A0A31003BFF1DF886
queryKey: EfSecondLevelCaching.Test.Models.Product
count: 3

Removing items with dependencyKey=EfSecondLevelCaching.Test.Models.Product
Available cached keys list:
count: 0
Available cached keys list:
count: 0

Adding new data: queryKey=02E6FE403B461E45C5508684156C1D10, dependencyKey=EfSecondLevelCaching.Test.Models.Product

Available cached keys list:
queryKey: 02E6FE403B461E45C5508684156C1D10
queryKey: EfSecondLevelCaching.Test.Models.Product
count: 2


Fetching object 'EfSecondLevelCaching.Test.Models.Product__02E6FE403B461E45C5508684156C1D10' from the cache.

This is not a big-bang rewrite; we will continue development on the master branch, and roll out changes incrementally on the 1.x release train. The 2.0.0 release will simply remove features that have been deprecated between now and then. Our goal is that you can move your Ember app to 2.0 incrementally, one sprint at a time. 

.NotSupportedException: The method 'Max' is not supported

C:\Program Files\Microsoft ASP.NET\ASP.NET Web Pages\v2.0\Assemblies
C:\Program Files\Microsoft ASP.NET\ASP.NET MVC 4\Assemblies

{E53F8FEA-EAE0-44A6-8774-FFD645390401}

{E3E379DF-F4C6-4180-9B81-6769533ABE47}

System.Web.Mvc, Version=3.0.0.0
System.Web.WebPages, Version=1.0.0.0
System.Web.Helpers, Version=1.0.0.0
System.Web.WebPages.Razor, Version=1.0.0.0

System.Web.Mvc, Version=4.0.0.0
System.Web.WebPages, Version=2.0.0.0
System.Web.Helpers, Version=2.0.0.0
System.Web.WebPages.Razor, Version=2.0.0.0

C:\Program Files\Microsoft ASP.NET\ASP.NET Web Pages\v1.0\Assemblies
C:\Program Files\Microsoft ASP.NET\ASP.NET MVC 3\Assemblies

C:\Program Files\Microsoft ASP.NET\ASP.NET Web Pages\v2.0\Assemblies
C:\Program Files\Microsoft ASP.NET\ASP.NET MVC 4\Assemblies

<appSettings>
  <add key="webpages:Version" value="2.0.0.0" />
  <add key="PreserveLoginUrl" value="true" />
</appSettings>

<configuration>
  <!--... elements deleted for clarity ...-->
 
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Helpers" 
             publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0" newVersion="2.0.0.0"/>
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Mvc" 
             publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="4.0.0.0"/>
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.WebPages" 
             publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0" newVersion="2.0.0.0"/>
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
</configuration>

    <pages>
      <namespaces>
        <add namespace="System.Web.Optimization" />
      </namespaces>
    </pages>

[ValidateAntiForgeryToken(Salt = "data123")]

using System.Collections.Generic;
using System.IO;
using System.Web;
using System.Web.Optimization;

namespace Common.WebToolkit
{
    /// <summary>
    /// A custom bundle orderer (IBundleOrderer) that will ensure bundles are 
    /// included in the order you register them.
    /// </summary>
    public class AsIsBundleOrderer : IBundleOrderer
    {
        public IEnumerable<FileInfo> OrderFiles(BundleContext context, IEnumerable<FileInfo> files)
        {
            return files;
        }
    }

    public static class BundleConfig
    {
        private static void addBundle(string virtualPath, bool isCss, params string[] files)
        {
            BundleTable.EnableOptimizations = true;

            var existing = BundleTable.Bundles.GetBundleFor(virtualPath);
            if (existing != null)
                return;

            var newBundle = isCss ? new Bundle(virtualPath, new CssMinify()) : new Bundle(virtualPath, new JsMinify());
            newBundle.Orderer = new AsIsBundleOrderer();

            foreach (var file in files)
                newBundle.Include(file);

            BundleTable.Bundles.Add(newBundle);
        }

        public static IHtmlString AddScripts(string virtualPath, params string[] files)
        {
            addBundle(virtualPath, false, files);
            return Scripts.Render(virtualPath);
        }

        public static IHtmlString AddStyles(string virtualPath, params string[] files)
        {
            addBundle(virtualPath, true, files);
            return Styles.Render(virtualPath);
        }

        public static IHtmlString AddScriptUrl(string virtualPath, params string[] files)
        {
            addBundle(virtualPath, false, files);
            return Scripts.Url(virtualPath);
        }

        public static IHtmlString AddStyleUrl(string virtualPath, params string[] files)
        {
            addBundle(virtualPath, true, files);
            return Styles.Url(virtualPath);
        }
    }
}

@using Common.WebToolkit

<link href="@BundleConfig.AddStyleUrl("~/Content/blueprint/print", "~/Content/blueprint/print.css")" rel="stylesheet" type="text/css" media="print"/>

@BundleConfig.AddScripts("~/Scripts/js",
                            "~/Scripts/jquery-1.8.0.min.js",
                            "~/Scripts/jquery.unobtrusive-ajax.min.js",
                            "~/Scripts/jquery.validate.min.js")

@BundleConfig.AddStyles("~/Content/css",
                            "~/Content/Site.css",
                            "~/Content/buttons.css")

http://site/Content/blueprint/print?v=hash

@BundleConfig.AddStyles("~/Content/noty/css",
                                "~/Content/noty/jquery.noty.css",
                                "~/Content/noty/noty_theme_default.css")