The type or namespace name 'PagedListRenderOptions' could not be found (are you missing a using directive or an assembly reference?)
var option = $('<option></option>').attr("value", data[i].Id).text(data[i].Title);
Most Famous OSS developer in .NET world
If you are a .NET developer, you must have heard/used a nuget package called Newtonsoft.Json (or JSON.NET). The package is maintained by a legendary developer named James Newton-King.
public static IEnumerable<TResult> OfType<TResult>(this IEnumerable source)
IEnumerable input = new object[] { "Apple", 33, "Sugar", 44, 'a', new DateTime()};
IEnumerable<string> query = input.OfType<string>();
foreach (var item in query)
{
Console.WriteLine(item);
} Apple Sugar
class Ingredient
{
public string Name { get; set; }
}
class DryIngredient : Ingredient
{
public int Grams { get; set; }
}
class WetIngredient : Ingredient
{
public int Millilitres { get; set; }
} IEnumerable<Ingredient> input = new Ingredient[]
{
new DryIngredient { Name = "Flour" },
new WetIngredient { Name = "Milk" },
new WetIngredient { Name = "Water" }
};
IEnumerable<WetIngredient> query = input.OfType<WetIngredient>();
foreach (WetIngredient item in query)
{
Console.WriteLine(item.Name);
} Milk Water
IEnumerable input = new object[]
{
"Apple", 33, "Sugar", 44, 'a', new DateTime()
};
IEnumerable<string> query = input.Cast<string>();
foreach (string item in query)
{
Console.WriteLine(item);
} Unhandled Exception: System.InvalidCastException: Unable to cast object of type 'System.Int32' to type 'System.String'.
IEnumerable input = new object[]{ "Apple", "Sugar", "Flour" };
IEnumerable<string> query =
from string i in input
select i;
foreach (var item in query)
{
Console.WriteLine(item);
} IEnumerable<string> input = new List<string> { "Apple", "Sugar", "Flour" };
string[] array = input.ToArray(); IEnumerable<string> input = new[] { "Apple", "Sugar", "Flour" };
List<string> list = input.ToList(); class Recipe
{
public int Id { get; set; }
public string Name { get; set; }
public int Rating { get; set; }
}
IEnumerable<Recipe> recipes = new[]
{
new Recipe { Id = 1, Name = "Apple Pie", Rating = 5 },
new Recipe { Id = 2, Name = "Cherry Pie", Rating = 2 },
new Recipe { Id = 3, Name = "Beef Pie", Rating = 3 }
};
Dictionary<int, Recipe> dict = recipes.ToDictionary(x => x.Id);
foreach (KeyValuePair<int, Recipe> item in dict)
{
Console.WriteLine($"Key={item.Key}, Recipe={item.Value}");
} Key=1, Recipe=Apple Pie Key=2, Recipe=Cherry Pie Key=3, Recipe=Beef Pie
class Recipe
{
public int Id { get; set; }
public string Name { get; set; }
public byte Rating { get; set; }
}
IEnumerable<Recipe> recipes = new[]
{
new Recipe { Id = 1, Name = "Apple Pie", Rating = 5 },
new Recipe { Id = 1, Name = "Banana Pie", Rating = 5 },
new Recipe { Id = 2, Name = "Cherry Pie", Rating = 2 },
new Recipe { Id = 3, Name = "Beef Pie", Rating = 3 }
};
ILookup<byte, Recipe> look = recipes.ToLookup(x => x.Rating);
foreach (IGrouping<byte, Recipe> ratingGroup in look)
{
byte rating = ratingGroup.Key;
Console.WriteLine($"Rating {rating}");
foreach (var recipe in ratingGroup)
{
Console.WriteLine($" - {recipe.Name}");
}
} Rating 5 - Apple Pie - Banana Pie Rating 2 - Cherry Pie Rating 3 - Beef Pie
Ingredient[] ingredients =
{
new Ingredient {Name = "Sugar", Calories = 500},
new Ingredient {Name = "Egg", Calories = 100},
new Ingredient {Name = "Milk", Calories = 150},
new Ingredient {Name = "Flour", Calories = 50},
new Ingredient {Name = "Butter", Calories = 500}
};
Ingredient element = ingredients.First();
Console.WriteLine(element.Name); Sugar
Ingredient[] ingredients =
{
new Ingredient {Name = "Sugar", Calories = 500},
new Ingredient {Name = "Egg", Calories = 100},
new Ingredient {Name = "Milk", Calories = 150},
new Ingredient {Name = "Flour", Calories = 50},
new Ingredient {Name = "Butter", Calories = 500}
};
Ingredient element = ingredients.First(x=>x.Calories==150);
Console.WriteLine(element.Name); Milk
Unhandled Exception: System.InvalidOperationException: Sequence contains no elements
Ingredient[] ingredients = { };
Ingredient element = ingredients.First(); Unhandled Exception: System.InvalidOperationException: Sequence contains no matching element
Ingredient[] ingredients =
{
new Ingredient {Name = "Sugar", Calories = 500},
new Ingredient {Name = "Egg", Calories = 100},
new Ingredient {Name = "Milk", Calories = 150},
new Ingredient {Name = "Flour", Calories = 50},
new Ingredient {Name = "Butter", Calories = 500}
};
Ingredient element = ingredients.First(x=>x.Calories==1500); Ingredient[] ingredients = { };
Ingredient element = ingredients.FirstOrDefault();
Console.WriteLine(element == null); True
Ingredient[] ingredients =
{
new Ingredient {Name = "Sugar", Calories = 500},
new Ingredient {Name = "Egg", Calories = 100},
new Ingredient {Name = "Milk", Calories = 150},
new Ingredient {Name = "Flour", Calories = 50},
new Ingredient {Name = "Butter", Calories = 500}
};
Ingredient element = ingredients.FirstOrDefault(x=>x.Calories==1500);
Console.WriteLine(element==null); True
Ingredient[] ingredients =
{
new Ingredient {Name = "Sugar", Calories = 500},
new Ingredient {Name = "Egg", Calories = 100},
new Ingredient {Name = "Milk", Calories = 150},
new Ingredient {Name = "Flour", Calories = 50},
new Ingredient {Name = "Butter", Calories = 500}
};
Ingredient element = ingredients.Last(x=>x.Calories==500);
Console.WriteLine(element.Name); Flour
Unhandled Exception: System.InvalidOperationException: Sequence contains more than one matching element Unhandled Exception: System.InvalidOperationException: Sequence contains no matching element
Ingredient[] ingredients =
{
new Ingredient { Name = "Sugar", Calories = 500 }
};
Ingredient element = ingredients.Single();
Console.WriteLine(element.Name); Sugar
Ingredient[] ingredients =
{
new Ingredient { Name = "Sugar", Calories = 500 },
new Ingredient {Name = "Butter", Calories = 150},
new Ingredient {Name = "Milk", Calories = 500}
};
Ingredient element = ingredients.Single(x => x.Calories == 150);
Console.WriteLine(element.Name); Butter
Ingredient[] ingredients =
{
new Ingredient { Name = "Sugar", Calories = 500 },
new Ingredient {Name = "Egg", Calories = 100},
new Ingredient {Name = "Milk", Calories = 50}
};
Ingredient element = ingredients.SingleOrDefault(x => x.Calories == 9999);
Console.WriteLine(element==null); True
Ingredient[] ingredients =
{
new Ingredient { Name = "Sugar", Calories = 500 },
new Ingredient {Name = "Egg", Calories = 100},
new Ingredient {Name = "Milk", Calories = 50}
};
Ingredient element = ingredients.ElementAt(2);
Console.WriteLine(element.Name); Milk
System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection.
Ingredient[] ingredients =
{
new Ingredient { Name = "Sugar", Calories = 500 },
new Ingredient {Name = "Egg", Calories = 100},
new Ingredient {Name = "Milk", Calories = 50}
};
Ingredient element = ingredients.ElementAtOrDefault(5);
Console.WriteLine(element==null); True
Ingredient[] ingredients =
{
new Ingredient { Name = "Sugar", Calories = 500 },
new Ingredient {Name = "Egg", Calories = 100},
new Ingredient {Name = "Milk", Calories = 50}
};
IEnumerable<Ingredient> query = ingredients.DefaultIfEmpty();
foreach (Ingredient item in query)
{
Console.WriteLine(item.Name);
} Sugar Egg Milk
Ingredient[] ingredients = { };
IEnumerable<Ingredient> query = ingredients.DefaultIfEmpty();
foreach (Ingredient item in query)
{
Console.WriteLine(item == null);
} True
{
"dependencies": {
"Microsoft.Extensions.Caching.SqlServer": "1.1.0"
},
"tools": {
"Microsoft.Extensions.Caching.SqlConfig.Tools": "1.1.0-preview4-final"
}
} dotnet sql-cache create "Data Source=(localdb)\MSSQLLocalDB;Initial Catalog=sql_cache;Integrated Security=True;" "dbo" "AppSqlCache"
CREATE TABLE AppSqlCache ( Id NVARCHAR (449) COLLATE SQL_Latin1_General_CP1_CS_AS NOT NULL, Value VARBINARY (MAX) NOT NULL, ExpiresAtTime DATETIMEOFFSET NOT NULL, SlidingExpirationInSeconds BIGINT NULL, AbsoluteExpiration DATETIMEOFFSET NULL, CONSTRAINT pk_Id PRIMARY KEY (Id) ); CREATE NONCLUSTERED INDEX Index_ExpiresAtTime ON AppSqlCache(ExpiresAtTime);
public class AppSqlCache
{
public string Id { get; set; }
public byte[] Value { get; set; }
public DateTimeOffset ExpiresAtTime { get; set; }
public long? SlidingExpirationInSeconds { get; set; }
public DateTimeOffset? AbsoluteExpiration { get; set; }
} public class MyDBDataContext : DbContext
{
public virtual DbSet<AppSqlCache> AppSqlCache { get; set; }
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<AppSqlCache>(entity =>
{
entity.ToTable(name: "AppSqlCache", schema: "dbo");
entity.HasIndex(e => e.ExpiresAtTime).HasName("Index_ExpiresAtTime");
entity.Property(e => e.Id).HasMaxLength(449);
entity.Property(e => e.Value).IsRequired();
});
}
} public void ConfigureServices(IServiceCollection services)
{
services.AddDistributedSqlServerCache(options =>
{
options.ConnectionString = @"Data Source=(localdb)\MSSQLLocalDB;Initial Catalog=sql_cache;Integrated Security=True;";
options.SchemaName = "dbo";
options.TableName = "AppSqlCache";
}); public IActionResult Index()
{
HttpContext.Session.SetString("User", "VahidN");
return Json(true);
}
public IActionResult About()
{
var userContent = HttpContext.Session.GetString("User");
return Json(userContent);
} 
services.Add(ServiceDescriptor.Singleton<IDistributedCache, SqlServerCache>());
using System;
using System.Text;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Caching.Distributed;
namespace Core1RtmEmptyTest.Controllers
{
public class CacheTestController : Controller
{
readonly IDistributedCache _cache;
public CacheTestController(IDistributedCache cache)
{
_cache = cache;
}
public IActionResult SetCacheData()
{
var time = DateTime.Now.ToLocalTime().ToString();
var cacheOptions = new DistributedCacheEntryOptions
{
AbsoluteExpiration = DateTime.Now.AddYears(1)
};
_cache.Set("Time", Encoding.UTF8.GetBytes(time), cacheOptions);
return View();
}
public IActionResult GetCacheData()
{
var time = Encoding.UTF8.GetString(_cache.Get("Time"));
ViewBag.data = time;
return View();
}
public bool RemoveCacheData()
{
_cache.Remove("Time");
return true;
}
}
} Value VARBINARY (MAX) NOT NULL,
public byte[] Value { get; set; } 
<distributed-cache name="MyCacheItem2" expires-sliding="TimeSpan.FromMinutes(30)"> <p>From distributed-cache</p> @DateTime.Now.ToString() </distributed-cache>
REACT_APP_NAME=My App REACT_APP_VERSION=1
console.log(process.env);
console.log("My App Name", process.env.REACT_APP_NAME); 
> npm install -g serve > serve -s build
Access to XMLHttpRequest at 'https://localhost:5001/api/genres' from origin 'http://localhost:1234' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.
WithOrigins("http://localhost:3000", "http://localhost:1234") REACT_APP_API_URL=https://localhost:5001/api REACT_APP_ADMIN_ROLE_NAME=Admin
const apiEndpoint = apiUrl + "/users";
const apiEndpoint = "/users";
axios.defaults.baseURL = process.env.REACT_APP_API_URL;
const adminRoleName = process.env.REACT_APP_ADMIN_ROLE_NAME;
public class XamAppExceptionHandler : BitExceptionHandler
{
public override void OnExceptionReceived(Exception exp, IDictionary<string, string> properties = null)
{
#if DEBUG
System.Diagnostics.Debugger.Break();
#endif
base.OnExceptionReceived(exp, properties);
}
} BitExceptionHandler.Current = new XamAppExceptionHandler();
حال برای لاگ کردن این خطاها، می‌توانید از Microsoft's AppCenter استفاده کنید. استفاده از امکانات App Center رایگان بوده و برای استفاده‌ی در ایران محدودیتی ندارد. ابتدا در سایت مربوطه ثبت نام کنید و سپس سه بار Add New app را بزنید و به نام‌های XamApp_Windows، XamApp_iOS و XamApp_Android سه برنامه را بسازید و برای Android و iOS گزینه‌ی Xamarin را انتخاب و برای ویندوز نیز UWP را انتخاب کنید.
سپس پکیج‌های Microsoft.AppCenter.Crashes و Microsoft.AppCenter.Analytics را بر روی XamApp نصب نموده و کد زیر را در سه فایل AppDelegate.cs/MainActivity.cs/App.xaml.cs برای iOS/Android/Windows کپی کنید:
AppCenter.Start("copy-your-guid-key-for-iOS-Android-Windows-here", typeof(Crashes), typeof(Analytics)); برای هر یک از برنامه‌های Android/iOS/Windows یک Guid متفاوت دارید که در قسمت Getting Started در سایت App Center می‌توانید آنها را مشاهده کنید. هر بار که این کد را کپی می‌کنید، مقدار Guid درست را بگذارید.
برای گزارش کردن خطاهای برنامه، کافی است کد زیر را به XamAppExceptionHandler.cs که در ابتدای این قسمت در موردش صحبت کرده بودیم اضافه کنید:
Crashes.TrackError(exp, properties);
حال اگر برنامه را اجرا و شروع به تست کنید و یا آن را در اختیار تسترها و مشتری‌ها بگذارید، نه تنها گزارش تمامی خطاها و کرش‌ها را خواهید داشت که حتی آمار استفاده کننده‌های برنامه (شامل کشور و مشخصات دستگاه و ...) را نیز خواهید داشت.
حال در یک کد ده خطی، اگر در خط پنجم خطایی رخ دهد، اگر چه باعث بسته شدن برنامه نمی‌شود و لاگ نیز می‌شود، ولی در مواقعی خیلی خاص، شاید بخواهید در صورت رخ دادن خطا، چند خط کد بعدی کماکان اجرا شوند. در این حالت شما Try/Catch می‌نویسید که برای عبور کردن از خطا از آن استفاده کرده‌اید. در این صورت، ترجیحا آن را به شکل زیر بنویسید:
// code 1...
try
{
// code 2...
}
catch (Exception ex)
{
BitExceptionHandler.Current.OnExceptionReceived(ex, new Dictionary<string, string>
{
{ "SomeData", "2" }
});
}
// code 3... در این کد مثال، فرض کنیم که برخی اوقات در code 2 خطایی رخ میدهد که برای ما مهم نیست و می‌خواهیم حتی در صورت رخ دادن خطا، code 3 اجرا شود. توصیه می‌کنیم در این موارد که در برنامه خیلی هم نباید متداول باشد، لااقل خطا را با کمک کد BitExceptionHandler.Current.OnExceptionReceived لاگ کنید و همچنین با داشتن یک Dictionary می‌توانید حتی دیتای بیشتری را نیز به AppCenter فرستاده و در پرتال مربوطه مشاهده کنید.
به صورت کلی بهتر است از این نوع Try/Catchها پرهیز کنید و حتی اگر جایی Catch ای نوشتید، در نهایت دوباره خطا را throw کنید.
try
{
// some codes...
}
catch
{
// Do something related to exception...
// for example, show some alerts to the user.
throw; // You don't need to call BitExceptionHandler.Current.OnExceptionReceived...
} در مثال فوق، قصد داریم وقتی خطایی رخ داد، پیامی را به کاربر اطلاع دهیم. در این صورت، پس از نمایش پیام مربوطه، مجددا خطا را throw کنید. در این صورت، نیازی به فراخوانی BitExceptionHandler.Current.OnExceptionReceieved نیز نیست.
البته AppCenter در زمینه پابلیش کردن برنامه و همچنین Push Notification و ... نیز دارای امکاناتی هست که به موضوع این قسمت ارتباطی ندارند.
PM> Install-Package Twitter.BootstrapRTL
PM> Install-Package Microsoft.AspNet.Web.Optimization
using System.Collections.Generic;
using System.IO;
using System.Web;
using System.Web.Optimization;
namespace Mvc4TwitterBootStrapTest.Helper
{
/// <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;
Bundle newBundle;
if (HttpContext.Current.IsDebuggingEnabled)
{
newBundle = new Bundle(virtualPath);
}
else
{
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 Mvc4TwitterBootStrapTest.Helper
<!DOCTYPE html>
<html>
<head>
<title>@ViewBag.Title</title>
@BundleConfig.AddStyles("~/Content/css",
"~/Content/bootstrap.css",
"~/Content/bootstrap-responsive.css",
"~/Content/Site.css"
)
@BundleConfig.AddScripts("~/Scripts/js",
"~/Scripts/jquery-1.9.1.min.js",
"~/Scripts/jquery.validate.min.js",
"~/Scripts/jquery.unobtrusive-ajax.min.js",
"~/Scripts/jquery.validate.unobtrusive.min.js",
"~/Scripts/bootstrap.min.js"
)
@RenderSection("JavaScript", required: false)
</head><!DOCTYPE html>
<html>
<head>
<title>Index</title>
<link href="/Content/css?v=vsUQD0OJg4AJ-RZH8jSRRCu_rjl2U1nZrmSsaUyxoAc1" rel="stylesheet"/>
<script src="/Scripts/js?v=GezdoTDiWY3acc3mI2Ujm_7nKKzh6Lu1Wr8TGyyLpW41"></script>
</head>
<body>
<div>
<div>
<h1>
Title Title
</h1>
Text Text Text Text Text Text Text Text Text Text Text Text Text Text Text Text
</div>
<div>
@RenderBody()
</div>
</div>
</body><body>
<div class="row">
<div class="span7">
<h1>
Title Title
</h1>
Text Text Text Text Text Text Text Text Text Text Text Text Text Text Text Text
</div>
<div class="span5">
@RenderBody()
</div>
</div>
</body>
@{
ViewBag.Title = "Index";
}
<h2>
Index</h2>
<div class="hero-unit">
<h2>@ViewBag.Message</h2>
<p>
This is a template to demonstrate the way to beautify the default MVC template
using Twitter Bootstrap website. It is pretty simple and easy.</p>
<p>
<a href="http://asp.net/mvc" class="btn btn-primary btn-large" style="color: White;">
To learn more about ASP.NET MVC visit »</a></p>
</div> <div class="row">
<div class="span1">1</div>
<div class="span1">1</div>
<div class="span1">1</div>
<div class="span1">1</div>
<div class="span1">1</div>
<div class="span1">1</div>
<div class="span1">1</div>
<div class="span1">1</div>
<div class="span1">1</div>
<div class="span1">1</div>
<div class="span1">1</div>
<div class="span1">1</div>
</div>
<div class="row">
<div class="span3">3</div>
<div class="span4">4</div>
<div class="span5">5</div>
</div>
<div class="row">
<div class="span5">5</div>
<div class="span7">7</div>
</div>
<div class="row">
<div class="span3">3</div>
<div class="span7 offset2">7 offset 2</div>
</div>
<div class="row">
<div class="span12">12</div>
</div>[class*="span"]
{
background-color: lightblue;
text-align: center;
margin-top: 15px;
}
@media (min-width: 768px) and (max-width: 979px) {
.hidden-desktop {
display: inherit !important;
} <div class="container-fluid">
<div class="row-fluid">
<div class="span4">
<div class="visible-phone">
visible-phone</div>
</div>
<div class="span4">
<div class="visible-tablet">
visible-tablet</div>
</div>
<div class="span4">
<div class="visible-desktop">
visible-desktop</div>
</div>
</div>
</div>
<div class="container-fluid">
<div class="row-fluid">
<div class="span4">
<div class="hidden-phone">
hidden-phone</div>
</div>
<div class="span4">
<div class="hidden-tablet">
hidden-tablet</div>
</div>
<div class="span4">
<div class="hidden-desktop">
hidden-desktop</div>
</div>
</div>
</div>
<Page user={user} /> <PageLayout user={user} /> <NavigationBar user={user} /> import React from "react";
export const UserContext = React.createContext({ user: {} });
export const UserProvider = UserContext.Provider;
export const UserConsumer = UserContext.Consumer; import "../../App.css";
import React, { Component } from "react";
import { UserProvider } from "../../contexts/userContext";
import Main from "./Main";
class App extends Component {
state = {
user: { name: "User 1" }
};
componentDidMount() {
// get user from the server or local storage and then set the currently logged in user to the this.state
}
render() {
return (
<>
<h1>App Class</h1>
<UserProvider value={this.state.user}>
<Main />
</UserProvider>
</>
);
}
}
export default App; export const DefaultRouteContext = React.createContext({ path: '/welcome' }); import React from "react";
import { UserConsumer } from "../../contexts/userContext";
export default function Main(props) {
return (
<>
<UserConsumer>
{value => <div>User name: {value.name}.</div>}
</UserConsumer>
</>
);
} 
import React, { useContext } from "react";
import { UserContext } from "../../contexts/userContext";
export default function Main() {
const value = useContext(UserContext);
return (
<>
<div>User name: {value.name}.</div>
</>
);
} function HeaderBar() {
return (
<CurrentUser.Consumer>
{user =>
<Notifications.Consumer>
{notifications =>
<header>
Welcome back, {user.name}!
You have {notifications.length} notifications.
</header>
}
}
</CurrentUser.Consumer>
);
} function HeaderBar() {
const user = useContext(CurrentUser);
const notifications = useContext(Notifications);
return (
<header>
Welcome back, {user.name}!
You have {notifications.length} notifications.
</header>
);
} import "../../App.css";
import React, { Component } from "react";
import { UserProvider } from "../../contexts/userContext";
import Main from "./Main2";
class App extends Component {
state = {
user: { name: "User 1" }
};
componentDidMount() {
// get user from the server or local storage and then set the currently logged in user to the this.state
}
logout = () => {
console.log("logout");
this.setState({ user: {} });
};
render() {
const contextValue = {
user: this.state.user,
logoutUser: this.logout
};
return (
<>
<h1>App Class</h1>
<UserProvider value={contextValue}>
<Main />
</UserProvider>
</>
);
}
}
export default App; import React, { useContext } from "react";
import { UserContext } from "../../contexts/userContext";
export default function Main() {
const { user, logoutUser } = useContext(UserContext);
return (
<>
<div>User name: {user.name}.</div>
<button type="button" className="btn btn-primary" onClick={logoutUser}>
Logout user
</button>
</>
);
} import React from "react";
import { UserConsumer } from "../../contexts/userContext";
export default function Main(props) {
return (
<>
<UserConsumer>
{({ user, logoutUser }) => (
<>
<div>User name: {user.name}.</div>
<button
type="button"
className="btn btn-primary"
onClick={logoutUser}
>
Logout user
</button>
</>
)}
</UserConsumer>
</>
);
}