public class Parent
{
  public Parent()
  {
            Console.WriteLine("Parent Constructor");
  }
  public void Print()
  {
            Console.WriteLine("Parent Print");
  }


}

public class Child : Parent
{
  public Child()
  {
           Console.WriteLine("Child Constructor");
  }

  public void Print()
  {
           Console.WriteLine("Child Print");
  }
}

 public new void Print()
  {
     Console.WriteLine("Child Print");
  }

Console.WriteLine("====Parent====");
Parent parent = new Parent();
parent.Print();

Console.WriteLine("====Child====");
Child child = new Child();
child.Print();

Console.WriteLine("====Parent Via Child====");
Parent pc = new Child();
pc.Print();

  public class Parent
{
  public Parent()
  {
Console.WriteLine("Parent Constructor");
  }

  public virtual void  Print()
  {
Console.WriteLine("Parent Print");
  }
}

public class Child : Parent
{
  public Child()
  {
Console.WriteLine("Child Constructor");
  }

  public override void Print()
  {
Console.WriteLine("Child Print");
  }
}

   public class Parent
{
  static Parent()
  {
Console.WriteLine("Parent static Constructor");
  }
  public Parent()
  {
Console.WriteLine("Parent Constructor");
  }

  public virtual void  Print()
  {
Console.WriteLine("Parent Print");
  }
}

public class Child : Parent
{
  static Child()
  {
Console.WriteLine("Child static Constructor");
  }
  public Child()
  {
Console.WriteLine("Child Constructor");
  }

  public override void Print()
  {
Console.WriteLine("Child Print");
  }

<?xml version="1.0" encoding="UTF-8" ? />
<OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.1/">
    <ShortName>My Site's Asset Finder</ShortName>
    <Description>Find all your assets</Description>
    <Url type="text/html"
        method="get"
        template="http://MySite.com/Home/Search/?q=searchTerms"/>
    <InputEncoding>UTF-8</InputEncoding>
    <SearchForm>http://MySite.com/</SearchForm>
</OpenSearchDescription>

using System;
using System.Text;
using System.Web;
using System.Web.Mvc;
using System.Xml;

namespace WebToolkit
{
    public class OpenSearchResult : ActionResult
    {
        public string ShortName { set; get; }
        public string Description { set; get; }
        public string SearchForm { set; get; }
        public string FavIconUrl { set; get; }
        public string SearchUrlTemplate { set; get; }

        public override void ExecuteResult(ControllerContext context)
        {
            if (context == null)
                throw new ArgumentNullException("context");

            var response = context.HttpContext.Response;
            writeToResponse(response);
        }

        private void writeToResponse(HttpResponseBase response)
        {
            response.ContentEncoding = Encoding.UTF8;
            response.ContentType = "application/opensearchdescription+xml";
            using (var xmlWriter = XmlWriter.Create(response.Output, new XmlWriterSettings { Indent = true }))
            {
                xmlWriter.WriteStartElement("OpenSearchDescription", "http://a9.com/-/spec/opensearch/1.1/");

                xmlWriter.WriteElementString("ShortName", ShortName);
                xmlWriter.WriteElementString("Description", Description);
                xmlWriter.WriteElementString("InputEncoding", "UTF-8");
                xmlWriter.WriteElementString("SearchForm", SearchForm);

                xmlWriter.WriteStartElement("Url");
                xmlWriter.WriteAttributeString("type", "text/html");
                xmlWriter.WriteAttributeString("template", SearchUrlTemplate);                
                xmlWriter.WriteEndElement();

                xmlWriter.WriteStartElement("Image");
                xmlWriter.WriteAttributeString("width", "16");
                xmlWriter.WriteAttributeString("height", "16");
                xmlWriter.WriteString(FavIconUrl);
                xmlWriter.WriteEndElement();

                xmlWriter.WriteEndElement();
                xmlWriter.Close();
            }
        }
    }
}

using System.Web.Mvc;

namespace Readers
{
    public partial class OpenSearchController : Controller
    {
        public virtual ActionResult Index()
        {
            var fullBaseUrl = Url.Action(result: MVC.Home.Index(), protocol: "http");
            return new OpenSearchResult
            {
                ShortName = ".NET Tips",
                Description = ".NET Tips Contents Search",
                SearchForm = fullBaseUrl,
                FavIconUrl = fullBaseUrl + "favicon.ico",
                SearchUrlTemplate = Url.Action(result: MVC.Search.Index(), protocol: "http") + "?term={searchTerms}"
            };
        }
    }
}

<link href="@Url.Action(result: MVC.OpenSearch.Index(), protocol: "http")" rel="search"
        title=".NET Tips Search"  type="application/opensearchdescription+xml" />

import React from "react";

const Rentals = () => {
  return <h1>Rentals</h1>;
};

export default Rentals;

@page "/razor"

@template
@ItemTemplate(emp)

@code {

    RenderFragment template = @<p>The time is @DateTime.Now.</p>;
    RenderFragment<Employee> ItemTemplate = (item) => @<p>Employee name is @item.Name.</p>;

    Employee emp = new Employee { Name = "Test" };

    public class Employee
    {
        public string Name;
    }
}

 @page "/"
  
 @CreateDynamicComponent()

 @code {
     RenderFragment CreateDynamicComponent() => builder =>
     {
         builder.OpenComponent(0, typeof(SurveyPrompt));
         builder.AddAttribute(1, "Title", "Some title");
         builder.CloseComponent();
     };
 }

تبدیل یک ساختار Relational به JSON 

میتوانیم خروجی موردنظر را در قالب JSON نیز کوئری بگیریم: 

SELECT 
    JSON_OBJECT('id',
            U.id,
            'user',
            CONCAT_WS(' ', U.first_name, U.last_name),
            'title',
            BP.title)
FROM
    Users AS U
        JOIN
    BlogPosts AS BP ON U.id = BP.user_id;

به عنوان مثال میتوانیم لیست کاربران را به همراه بلاگ پست‌هایشان، اینگونه کوئری بگیریم: 

SELECT 
    JSON_OBJECT('user',
            CONCAT_WS(' ', U.first_name, U.last_name),
            'blog_posts',
            JSON_ARRAYAGG(JSON_OBJECT('id', BP.id, 'title', BP.title))) AS JSON
FROM
    Users AS U
        JOIN
    BlogPosts AS BP ON U.id = BP.user_id
GROUP BY U.id;

خروجی کوئری فوق اینچنین خواهد بود:

تبدیل یک ساختار JSON به Relational 

همچنین میتوانیم یک ساختار JSON را به صورت Relational تبدیل کنیم. اینکار توسط تابع JSON_TABLE قابل انجام است. کاری که این تابع انجام میدهد، ایجاد یک جدول موقت و کپی کردن دیتای موردنظر درون آن است. فرض کنید ساختار JSON زیر را به اینصورت درون دیتابیس ذخیره کرده‌ایم:

{
  "id": "1",
  "new": false,
  "sku": "asdf123",
  "tag": ["fashion", "men", "jacket", "full sleeve"],
  "name": "Lorem ipsum jacket",
  "image": [
    "/assets/img/product/fashion/1.jpg",
    "/assets/img/product/fashion/3.jpg",
    "/assets/img/product/fashion/6.jpg",
    "/assets/img/product/fashion/8.jpg",
    "/assets/img/product/fashion/9.jpg"
  ],
  "price": 12.45,
  "rating": 4,
  "category": ["fashion", "men"],
  "discount": 10,
  "offerEnd": "October 5, 2020 12:11:00",
  "saleCount": 54,
  "description": {
    "fullDescription": "Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam, eaque ipsa quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt explicabo. Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt ut labore et dolore magnam aliquam quaerat voluptatem. Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur? Quis autem vel eum iure reprehenderit qui in ea voluptate velit esse quam nihil molestiae consequatur, vel illum qui dolorem eum fugiat quo voluptas nulla pariatur? Nor again is there anyone who loves or pursues or desires to obtain pain of itself, because it is pain, but because occasionally circumstances occur in which toil and pain can procure him some great pleasure. To take a trivial example, which of us ever undertakes laborious physical exercise, except to obtain some advantage from it? But who has any right to find fault with a man who chooses to enjoy a pleasure that has no annoying consequences, or one who avoids a pain that produces no resultant pleasure?",
    "shortDescription": "Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur? Quis autem vel eum iure reprehenderit qui in ea voluptate velit esse quam nihil molestiae consequatur."
  }
}

اکنون میخواهیم چنین خروجی‌ای داشته باشیم: 

کوئری موردنیاز برای تهیه خروجی فوق اینچنین خواهد بود: 

SELECT newTable.* 
FROM experiments.productMetadata,
JSON_TABLE(
data,
    "$" COLUMNS (
id INT PATH "$.id",
        new CHAR(5) PATH "$.new",
        sku CHAR(20) PATH "$.sku",
        price FLOAT PATH "$.price",
        rating FLOAT PATH "$.rating",
        name CHAR(255) PATH "$.name",
        discount FLOAT PATH "$.discount",
        offerEnd TEXT PATH "$.offerEnd",
        saleCount INT PATH "$.saleCount",
        description TEXT PATH "$.description.shortDescription"
    )
) AS newTable;

تابع JSON_TABLE دو ورودی نیاز خواهد داشت؛ ورودی اول ستون JSONی است که میخوایم از آن کوئری بگیریم. ورودی دوم با تعیین path شروع خواهد شد. از آنجائیکه محتوای داخل ستون data به صورت آبجکت ذخیره شده‌است، از $ استفاده کرده‌ایم که به معنای داکیومنت جاری است. سپس توسط کلمه کلیدی COLUMNS ساختار جدول موقت‌مان را تعریف خواهیم کرد. این ساختار به صورت یک آرگومان به COLUMNS ارسال خواهد شد و شبیه به ساختار CREATE TABLE است؛ با این تفاوت که بعد از تعریف نوع داده‌ای هر ستون باید مسیر رسیدن به مقدار موردنظر را نیز تعیین کنیم که در واقع همان سینتکس pathی است که در مثالهای قبل نیز بررسی کردیم. به عنوان مثال برای رسیدن به مقدار پراپرتی name، مسیر را به صورت name.$ نوشته‌ایم. این path از آرایه نیز پشتیبانی میکند؛ مثلاً برای دسترسی به عنصر اول آرایه tag کافی است اینگونه عمل کنیم: 

tag CHAR(20) PATH "$.tag[0]"

همچنین تابع JSON_TABLE، از ساختارهای تودرتو نیز پشتیبانی میکند. به عنوان مثال برای داشتن مقادیر tag, category, image در خروجی میتوانیم از کلمه کلیدی NESTED استفاده کنیم: 

SELECT newTable.* 
FROM experiments.productMetadata,
JSON_TABLE(
data,
    "$" COLUMNS (
id INT PATH "$.id",
        new CHAR(5) PATH "$.new",
        sku CHAR(20) PATH "$.sku",
        price FLOAT PATH "$.price",
        rating FLOAT PATH "$.rating",
        NESTED PATH '$.tag[*]' COLUMNS (tag TEXT PATH '$'),
        name CHAR(255) PATH "$.name",
        discount FLOAT PATH "$.discount",
        offerEnd TEXT PATH "$.offerEnd",
        saleCount INT PATH "$.saleCount",
        description TEXT PATH "$.description.shortDescription",
        NESTED PATH '$.image[*]' COLUMNS (image TEXT PATH '$'),
        NESTED PATH '$.category[*]' COLUMNS (category TEXT PATH '$')
    )
) AS newTable;

درون COLUMNS میتوانیم یک name FOR ORDINALITY نیز تعیین کنیم. این فیلد دقیقاً مشابه AUTO INCREMENT در ساختار CREATE TABLE میباشد. به این معنا که به ازای هر آیتم فیلد nested، یک واحد اضافه خواهد شد. از آن میتوانیم به عنوان rowId برای آیتم آرایه استفاده کنیم:

NESTED PATH '$.category[*]' COLUMNS (categoryRowId FOR ORDINALITY, category TEXT PATH '$')

همچنین از ON EMPTY برای پراپرتی‌هایی که در ساختار JSON وجود ندارند نیز میتوانیم استفاده کنیم. به عنوان مثال در کوئری زیر گفته‌ایم در صورت عدم وجود price، یک مقدار پیش‌فرض باید نمایش داده شود و همچنین در صورت عدم وجود name، یک خطا در خروجی نمایش داده شود:

name CHAR(255) PATH "$.name" ERROR ON EMPTY,
price FLOAT PATH "$.price" DEFAULT "0" ON EMPTY,

همچنین میتوانیم مقدار NULL را در صورت عدم وجود name ست کنیم:

name CHAR(255) PATH "$.name" NULL ON EMPTY,

export class PagedQueryModel {
  constructor(
    // ...
    public filterByColumn: string,
    public filterByValue: string,
  ) { }
}

  doFilter() {
    this.queryModel.page = 1;
    this.getPagedProductsList();
  }

  resetFilter() {
    this.queryModel.page = 1;
    this.queryModel.filterByColumn = "";
    this.queryModel.filterByValue = "";
    this.getPagedProductsList();
  }

<div class="panel panel-default">
  <div class="panel-body">
    <div class="form-group">
      <input type="text" [(ngModel)]="queryModel.filterByValue" placeholder="Search For ..."
        class="form-control" />
    </div>
    <div class="form-group">
      <select class="form-control" name="filterColumn" [(ngModel)]="queryModel.filterByColumn">
        <option value="">Filter by ...</option>
        <option *ngFor="let column of columns" [value]="column.propertyName">
          {{ column.title }}
        </option>
      </select>
    </div>
    <button class="btn btn-primary" type="button" (click)="doFilter()">Search</button>
    <button class="btn btn-default" type="button" (click)="resetFilter()">Reset</button>
  </div>
</div>

    public interface IPagedQueryModel
    {
    // ....
        string FilterByColumn { get; set; }
        string FilterByValue { get; set; }
    }

    public class ProductQueryViewModel : IPagedQueryModel
    {
        // ... other properties ...

// ...
        public string FilterByColumn { get; set; }
        public string FilterByValue { get; set; }
    }

    public static class IQueryableExtensions
    {
        public static IQueryable<T> ApplyFiltering<T>(
          this IQueryable<T> query,
          IPagedQueryModel model,
          IDictionary<string, Expression<Func<T, object>>> columnsMap)
        {
            if (string.IsNullOrWhiteSpace(model.FilterByValue) || !columnsMap.ContainsKey(model.FilterByColumn))
            {
                return query;
            }

            var func = columnsMap[model.FilterByColumn].Compile();
            return query.Where(x => func(x).ToString() == model.FilterByValue);
        }

var columnsMap = new Dictionary<string, Expression<Func<Product, object>>>()
            {
                ["productId"] = p => p.ProductId,
                ["productName"] = p => p.ProductName,
                ["isAvailable"] = p => p.IsAvailable,
                ["price"] = p => p.Price
            };
query = query.ApplyFiltering(queryModel, columnsMap);
query = query.ApplyOrdering(queryModel, columnsMap);

<xsl:stylesheet version="1.0"xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

<xsl:transform version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

<xsl:template match="/">
<html>
....
</html>
</xsl:template>

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="index.xslt"?>

<xsl:for-each select="Albums/Album">
<xsl:sort select="name"/>

<xsl:template match="DateOfRelease">

  <xsl:variable name="date" select="."/>
  <xsl:variable name="day" select="substring($date,1,2)"/>
  <xsl:variable name="month" select="number(substring($date,4,2))"/>
  <xsl:variable name="year" select="substring($date,7,4)"/>
  Release Date:

  <xsl:choose>
    <xsl:when test="$month = 1">
      <xsl:value-of select="$day"/>,Jan/<xsl:value-of select="$year"/>
    </xsl:when>
    <xsl:when test="$month = 2">
      <xsl:value-of select="$day"/>,Feb/<xsl:value-of select="$year"/>
    </xsl:when>
    <xsl:when test="$month = 3">
      <xsl:value-of select="$day"/>,Mar/<xsl:value-of select="$year"/>
    </xsl:when>
    <xsl:when test="$month = 4">
      <xsl:value-of select="$day"/>,Apr/<xsl:value-of select="$year"/>
    </xsl:when>
    <xsl:when test="$month = 5">
      <xsl:value-of select="$day"/>,May/<xsl:value-of select="$year"/>
    </xsl:when>
    <xsl:when test="$month = 6">
      <xsl:value-of select="$day"/>,Jun/<xsl:value-of select="$year"/>
    </xsl:when>

    <xsl:when test="$month = 7">
      <xsl:value-of select="$day"/>,Jul/<xsl:value-of select="$year"/>
    </xsl:when>
    <xsl:when test="$month = 8">
      <xsl:value-of select="$day"/>,Aug/<xsl:value-of select="$year"/>
    </xsl:when>
    <xsl:when test="$month = 9">
      <xsl:value-of select="$day"/>,Sep/<xsl:value-of select="$year"/>
    </xsl:when>
    <xsl:when test="$month = 10">
      <xsl:value-of select="$day"/>,Oct/<xsl:value-of select="$year"/>
    </xsl:when>
    <xsl:when test="$month = 11">
      <xsl:value-of select="$day"/>,Nov/<xsl:value-of select="$year"/>
    </xsl:when>

    <xsl:otherwise>
      <xsl:value-of select="$day"/>,Dec/<xsl:value-of select="$year"/>
    </xsl:otherwise>
  </xsl:choose>
</xsl:template>

<xsl:for-each select="Albums/Album">
  <xsl:sort select="name"/>
  <div>
    <img src="{cover}" width="200px" height="200px">
      <xsl:value-of select="cover" />
    </img>
    <h3>
      <xsl:value-of select="name" />
    </h3>
    <h4>POP</h4>

    <xsl:variable name="numprice" select="number(substring(price,1,string-length(price)-1))" />
    <xsl:choose>
      <xsl:when test="$numprice>=10">
        <h4 >
          <span style='text-decoration:line-through;color:red'>
            <xsl:value-of select="price" />
          </span>
          <b>
            <xsl:value-of select="$numprice -2" />$
          </b>
        </h4>
      </xsl:when>

      <xsl:otherwise>
        <h4 >
          <b>
            <xsl:value-of select="$numprice -2" />$
          </b>
        </h4>
      </xsl:otherwise>
    </xsl:choose>
    <h4>
      <!-- محل صدا زدن قالب-->
      <xsl:apply-templates select="DateOfRelease"/>
    </h4>
    <h4>
      <xsl:value-of select="Description"/>
    </h4>
    <div>
      <a href="#">More</a>
    </div>
  </div>
</xsl:for-each>

فیلترسازی
یکی از خصوصیات دیگری که فایل XML داشت، فیلد ژانر موسیقی بود و قصد داریم با استفاده از فیلترسازی، تنها سبک خاصی مثل سبک پاپ را نمایش دهیم و موسیقی‌هایی را که خارج از این سبک هستند، از نتیجه حذف کنیم. به همین علت دستور for-each را به شکل زیر تغییر میدهیم:

<xsl:for-each select="Albums/Album[contains(Genres/Genre, 'POP')]">

<xsl:for-each select="Albums/Album[not(contains(Genres/Genre, 'POP'))]">

<xsl:for-each select="Genres/Genre">
<xsl:value-of select="."/>
<xsl:if test="position() != last()">
,
</xsl:if>
</xsl:for-each>

تبدیل xml و xsl در دات نت

string xmlfile = Application.StartupPath + "\\sampleXML.xml";

//بارگذاری فایل قوانین در حافظه
XslTransform xslt = new XslTransform();
xslt.Load("sample-stylesheet.xsl");

//XPath ایجاد یک سند جدید بر اساس استاندارد 
XPathDocument xpath = new XPathDocument(xmlfile);

//آماده سازی برای نوشتن فایل نهایی
XmlTextWriter xwriter = new XmlTextWriter(xmlfile + ".html", Encoding.UTF8);

//نوشتن فایل مقصد بر اساس قوانین مشخص شده
xslt.Transform(xpath, null, xwriter, null);
xwriter.Close();

XsltArgumentList xslArgs = new XsltArgumentList();
xslArgs.AddParam("logo", "", logo);
xslArgs.AddParam("name", "", name); 
....
xslt.Transform(xpath, xslArgs, xwriter, null);

    public class ProductService
    {
        public IEnumerable<Product> GetOrderedProducts()
        {
            using (var ctx = new Entites())
            {
                return ctx.Products.OrderBy(x => x.Name).ToList();
            }
        }
    }

• Using Entity Framework in integration tests
  
• How We Do Database Integration Tests With Entity Framework Migrations
  

    public class ProductService
    {
        private readonly IDbSet<Product> _products;
        private readonly IUnitOfWork _uow;
        public ProductService(IUnitOfWork uow)
        {
            _uow = uow;
            _products = _uow.Set<Product>();
        }
     public IEnumerable<Product> GetOrderedProducts()
        {
            return _products.OrderBy(x => x.Name).ToList();
        }
    }

   [TestFixture]
    public class ProductServiceTest
    {
        private readonly ProductService _productService;
        public ProductServiceTest()
        {
            IQueryable<Product> data = GetRoadNetworks().AsQueryable();
            var mockSet = new Mock<DbSet<Product>>();
            mockSet.As<IQueryable<Product>>().Setup(m => m.Provider).Returns(data.Provider);
            mockSet.As<IQueryable<Product>>().Setup(m => m.Expression).Returns(data.Expression);
            mockSet.As<IQueryable<Product>>().Setup(m => m.ElementType).Returns(data.ElementType);
            mockSet.As<IQueryable<Product>>().Setup(m => m.GetEnumerator()).Returns(data.GetEnumerator());
            var context = new Mock<Entites>();
            context.Setup(c => c.Products).Returns(mockSet.Object);
            context.Setup(m => m.Set<Product>()).Returns(mockSet.Object);
            _productService = new ProductService(context.Object);
        }
        private IEnumerable<Product> GetRoadNetworks()
        {
            return new List<Product>
            {
                new Product
                {
                    Id = 1,
                    Name = "A"
                },
                new Product
                {
                    Id = 2,
                    Name = "B"
                },
                new Product
                {
                    Id = 3,
                    Name = "C"
                }
            };
        }
        [Test]
        public void GetOrderedProductTest()
        {
            IEnumerable<Product> products = _productService.GetOrderedProducts();
            List<string> names = products.Select(x => x.Name).ToList();
            var expected = new List<string> {"A", "B", "C"};
            CollectionAssert.AreEqual(names, expected);
        }
    }

services.AddDbContext<ApplicationDbContext>(options => options.UseSqlServer(connectionString));

public static IServiceCollection AddDbContext<TContext>(
    [NotNullAttribute] this IServiceCollection serviceCollection, 
    [CanBeNullAttribute] Action<DbContextOptionsBuilder> optionsAction = null, 
    ServiceLifetime contextLifetime = ServiceLifetime.Scoped, 
    ServiceLifetime optionsLifetime = ServiceLifetime.Scoped) where TContext : DbContext;

 An exception occurred while iterating over the results of a query for context type 'BlazorServer.DataAccess.ApplicationDbContext'.
System.InvalidOperationException: A second operation was started on this context before a previous operation completed.
This is usually caused by different threads concurrently using the same instance of DbContext.
For more information on how to avoid threading issues with DbContext, see https://go.microsoft.com/fwlink/?linkid=2097913.

public void ConfigureServices(IServiceCollection services)
{
    var connectionString = Configuration.GetConnectionString("DefaultConnection");
    //services.AddDbContext<ApplicationDbContext>(options => options.UseSqlServer(connectionString));
    services.AddDbContextFactory<ApplicationDbContext>(options => options.UseSqlServer(connectionString));

@inject IDbContextFactory<ApplicationDbContext> DbFactory

private async Task DeleteImageAsync()
{
    using var context = DbFactory.CreateDbContext();

    var image = await context.HotelRoomImages.FindAsync(1);

   // ...
}

@implements IDisposable
@inject IDbContextFactory<ApplicationDbContext> DbFactory


@code
{
   private ApplicationDbContext Context;

   protected override async Task OnInitializedAsync()
   {
       Context = DbFactory.CreateDbContext();
       await base.OnInitializedAsync();
   }

   private async Task DeleteImageAsync()
   {
       var image = await Context.HotelRoomImages.FindAsync(1);
       // ...
   }

   public void Dispose()
   {
     Context.Dispose();
   }
}

services.AddScoped<ApplicationDbContext>(serviceProvider =>
     serviceProvider.GetRequiredService<IDbContextFactory<ApplicationDbContext>>().CreateDbContext());

public interface IHotelRoomService : IDisposable
{
   // ...
}

public interface IHotelRoomImageService : IDisposable
{
   // ...
}

    public class HotelRoomService : IHotelRoomService
    {
        private bool _isDisposed;

        // ...

        public void Dispose()
        {
            Dispose(disposing: true);
            GC.SuppressFinalize(this);
        }

        protected virtual void Dispose(bool disposing)
        {
            if (!_isDisposed)
            {
                try
                {
                    if (disposing)
                    {
                        _dbContext.Dispose();
                    }
                }
                finally
                {
                    _isDisposed = true;
                }
            }
        }
    }

@page "/hotel-room/create"
@page "/hotel-room/edit/{Id:int}"

@implements IDisposable
// ...


@code
{
    // ...

    public void Dispose()
    {
        HotelRoomImageService.Dispose();
        HotelRoomService.Dispose();
    }
}

@page "/hotel-room"

@implements IDisposable
// ...


@code
{
    // ...

    public void Dispose()
    {
        HotelRoomService.Dispose();
    }
}

System.ObjectDisposedException: Cannot access a disposed context instance.
A common cause of this error is disposing a context instance that was resolved from dependency injection and then
later trying to use the same context instance elsewhere in your application. This may occur if you are calling 'Dispose'
on the context instance, or wrapping it in a using statement. If you are using dependency injection, you should let the
dependency injection container take care of disposing context instances.
Object name: 'ApplicationDbContext'.

@code
{
   private IHotelRoomImageService HotelRoomImageService;

   protected override async Task OnInitializedAsync()
   {
       HotelRoomImageService =  new HotelRoomImageService(DbFactory.CreateDbContext(), mapper);
       await base.OnInitializedAsync();
   }

   private async Task DeleteImageAsync()
   {
       await HotelRoomImageService.DeleteAsync(1);
       // ...
   }

   public void Dispose()
   {
     HotelRoomImageService.Dispose();
   }
}

@page "/hotel-room"

@*@implements IDisposable*@
@*@inject IHotelRoomService HotelRoomService*@
@inherits OwningComponentBase<IHotelRoomService>

@code
{
   private IHotelRoomService HotelRoomService => Service;

@page "/preferences"
@using Microsoft.Extensions.DependencyInjection
@inherits OwningComponentBase


@code {
    private IHotelRoomService HotelRoomService { get; set; }
    private IHotelRoomImageService HotelRoomImageService { get; set; }

    protected override void OnInitialized()
    {
        HotelRoomService = ScopedServices.GetRequiredService<IHotelRoomService>();
        HotelRoomImageService = ScopedServices.GetRequiredService<IHotelRoomImageService>();
    }
}

services.AddDbContextFactory<ApplicationDbContext>(options => options.UseSqlServer(connectionString));
services.AddScoped<ApplicationDbContext>(serviceProvider =>
        serviceProvider.GetRequiredService<IDbContextFactory<ApplicationDbContext>>().CreateDbContext());

@inject IHotelRoomService HotelRoomService

@inherits OwningComponentBase<IHotelRoomService>

this._pages.Include(page => page.Children).ToList().Where(page => page.Parent == null).ToList();

public class NavBarModel
    {
        public virtual int Id { get; set; }
        public virtual string Title { get; set; }
        public virtual string Status { get; set; }
        public virtual int? Order { get; set; }
        public virtual NavBarModel Parent { get; set; }
        public virtual ICollection<Page> Children { get; set; }
    }