The ASP.NET team is proud to announce general availability of ASP.NET Core 2.0. This release features compatibility with .NET Core 2.0, tooling support in Visual Studio 2017 version 15.3, and the new Razor Pages user-interface design paradigm. For a full list of updates, you can read the release notes. The latest SDK and tools can be downloaded from https://dot.net/core. Read the .NET Core 2.0 release announcement for more information and watch the launch video on Channel 9.
explore what's new in C# 8, as well as what we can expect in the near (and far) future of C#!
We'll talk about:
- News in C# 8
- Pattern Matching (incl. Record Types)
- Nullable Reference Types and How to Avoid Null Reference Exceptions
- How Async & Await is Improving
C# 8 was officially released in September at .NET Conf along side .NET Core 3 & Visual Studio 16.3 (8.3 on Mac). It is packed with tons of amazing new features that truly everyone should be using.
We are thrilled to announce the highly anticipated .NET Conf 2024, a free, three-day virtual developer event celebrating the release of .NET 9. Co-organized by the .NET community and Microsoft, this annual tradition continues to grow, and we’re more excited than ever to bring you the latest innovations in .NET. Mark your calendars for November 12th to 14th, 2024, and prepare to be inspired by a wealth of knowledge, creativity, and community engagement.
dotnet new blazor --interactivity Server
dotnet new blazor --interactivity WebAssembly
dotnet new blazor --interactivity Auto
dotnet new blazor --interactivity None
var builder = WebApplication.CreateBuilder(args);
builder.Services.AddRazorComponents().AddInteractiveServerComponents();
var app = builder.Build();
if (!app.Environment.IsDevelopment())
{
app.UseExceptionHandler("/Error", createScopeForErrors: true);
app.UseHsts();
}
app.UseHttpsRedirection();
app.UseStaticFiles();
app.UseAntiforgery();
app.MapRazorComponents<App>().AddInteractiveServerRenderMode();
app.Run(); @page "/counter"
@rendermode InteractiveServer
<PageTitle>Counter</PageTitle>
<h1>Counter</h1>
<p role="status">Current count: @currentCount</p>
<button class="btn btn-primary" @onclick="IncrementCount">Click me</button>
@code {
private int currentCount = 0;
private void IncrementCount()
{
currentCount++;
}
} @rendermode InteractiveServerRenderModeWithoutPrerendering
@code{
static readonly IComponentRenderMode InteractiveServerRenderModeWithoutPrerendering =
new InteractiveServerRenderMode(false);
} <!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<base href="/" />
<link rel="stylesheet" href="bootstrap/bootstrap.min.css" />
<link rel="stylesheet" href="app.css" />
<link rel="stylesheet" href="MyApp.styles.css" />
<link rel="icon" type="image/png" href="favicon.png" />
<HeadOutlet />
</head>
<body>
<Routes />
<script src="_framework/blazor.web.js"></script>
</body>
</html> <HeadOutlet @rendermode="@InteractiveServer" /> ... <Routes @rendermode="@InteractiveServer" />
@page "/weather"
@attribute [StreamRendering(prerender: true)]
<PageTitle>Weather</PageTitle>
<h1>Weather</h1>
<p>This component demonstrates showing data.</p>
@if (_forecasts == null)
{
<p>
<em>Loading...</em>
</p>
}
else
{
<table class="table">
<thead>
<tr>
<th>Date</th>
<th>Temp. (C)</th>
<th>Temp. (F)</th>
<th>Summary</th>
</tr>
</thead>
<tbody>
@foreach (var forecast in _forecasts)
{
<tr>
<td>@forecast.Date.ToShortDateString()</td>
<td>@forecast.TemperatureC</td>
<td>@forecast.TemperatureF</td>
<td>@forecast.Summary</td>
</tr>
}
</tbody>
</table>
}
@code {
private List<WeatherForecast>? _forecasts;
protected override async Task OnInitializedAsync()
{
// Simulate asynchronous loading to demonstrate streaming rendering
await Task.Delay(500);
var startDate = DateOnly.FromDateTime(DateTime.Now);
var summaries = new[]
{
"Freezing",
"Bracing",
"Chilly",
"Cool",
"Mild",
"Warm",
"Balmy",
"Hot",
"Sweltering",
"Scorching",
};
_forecasts = GetWeatherForecasts(startDate, summaries).ToList();
StateHasChanged();
// Simulate asynchronous loading to demonstrate streaming rendering
await Task.Delay(1000);
_forecasts.AddRange(GetWeatherForecasts(startDate, summaries));
StateHasChanged();
await Task.Delay(1000);
_forecasts.AddRange(GetWeatherForecasts(startDate, summaries));
}
private static IEnumerable<WeatherForecast> GetWeatherForecasts(DateOnly startDate, string[] summaries)
{
return Enumerable.Range(1, 5)
.Select(index => new WeatherForecast
{
Date = startDate.AddDays(index),
TemperatureC = Random.Shared.Next(-20, 55),
Summary = summaries[Random.Shared.Next(summaries.Length)],
});
}
private class WeatherForecast
{
public DateOnly Date { get; set; }
public int TemperatureC { get; set; }
public string? Summary { get; set; }
public int TemperatureF => 32 + (int)(TemperatureC / 0.5556);
}
} @using static Microsoft.AspNetCore.Components.Web.RenderMode
@attribute [RenderModeInteractiveServer]
@rendermode InteractiveServer
@rendermode renderMode
@code {
static IComponentRenderMode renderMode = new InteractiveWebAssemblyRenderMode(prerender: false);
} var integerArray = new int[3]; var lastItem = integerArray[integerArray.Length - 1];
var integerList = integerArray.ToList(); integerList.Last();
var secondToLast = integerArray[integerArray.Length - 2];
var lastItem = integerArray[^1];
var words = new string[]
{
// index from start index from end
"The", // 0 ^9
"quick", // 1 ^8
"brown", // 2 ^7
"fox", // 3 ^6
"jumped", // 4 ^5
"over", // 5 ^4
"the", // 6 ^3
"lazy", // 7 ^2
"dog" // 8 ^1
}; // 9 (or words.Length) ^0 Console.WriteLine($"The last word is {words[words.Length - 1]}"); 
var index = new Index(value: 1, fromEnd: true); Index indexStruct = ^1; var indexShortHand = ^1;
int[] a = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
Console.WriteLine(a[a.Length – 2]); // will write 8 on console.
Console.WriteLine(a[^2]); // will write 8 on console.
Index i5 = 5;
Console.WriteLine(a[i5]); //will write 5 on console.
Index i2fromEnd = ^2;
Console.WriteLine(a[i2fromEnd]); // will write 8 on console. var numbers = Enumerable.Range(1, 10).ToArray();
var (start, end) = (1, 7); var length = end - start; // Using LINQ var subset1 = numbers.Skip(start).Take(length); // Or using Array.Copy var subset2 = new int[length]; Array.Copy(numbers, start, subset2, 0, length);
var myArray = new string[] { "Item1", "Item2", "Item3", "Item4", "Item5" }; var fromIndexToX = myArray[1..3]; // = [Item2, Item3]
var fromIndexToXFromTheEnd = myArray[1..^1]; // = [ "Item2", "Item3", "Item4" ]
var fromAnIndexToTheEnd = myArray[1..]; // = [ "Item2", "Item3", "Item4", "Item5" ]
var fromTheStartToAnIndex = myArray[..3]; // = [ "Item1", "Item2", "Item3" ]
var entireRange = myArray[..]; // = [ "Item1", "Item2", "Item3", "Item4", "Item5" ]
var myArray = new string[] { "Item1", "Item2", "Item3", "Item4", "Item5" };
for (int i = 1; i <= 3; i++)
{
Console.WriteLine(myArray[i]);
} foreach (var item in myArray[1..4]) // = [ "Item2", "Item3", "Item4" ]
{
Console.WriteLine(item);
} using System;
using System.Linq;
namespace ConsoleApp
{
class Program
{
private static readonly int[] _numbers = Enumerable.Range(1, 10).ToArray();
static void Main()
{
var skip2CharactersAndTake2Characters = _numbers[2..4]; // صرفنظر کردن از دو عنصر اول و سپس انتخاب دو عنصر
var skipFirstAndLastCharacter = _numbers[1..^1]; // صرفنظر کردن از دو عنصر اول و آخر
var last3Characters = _numbers[^3..]; // انتخاب بازهای شامل سه عنصر آخر
var first4Characters = _numbers[0..4]; // دریافت بازهای از 4 عنصر اول
var rangeStartFrom2 = _numbers[2..]; // دریافت بازهای شروع شده از المان دوم تا آخر
var skipLast3Characters = _numbers[..^3]; // صرفنظر کردن از سه المان آخر
var rangeAll = _numbers[..]; // انتخاب کل بازه
}
}
} var range = new Range(1, 4); Range rangeStruct = 1..4; var rangeShortHand = 1..4;
using System;
using System.Linq;
namespace ConsoleApp
{
class Program
{
private static readonly int[] _numbers = Enumerable.Range(1, 10).ToArray();
static void Print(Range range) => Console.WriteLine($"{range} => {string.Join(", ", _numbers[range])}");
static void Main()
{
Print(1..3); // 1..3 => 2, 3
Print(..3); // 0..3 => 1, 2, 3
Print(3..); // 3..^0 => 4, 5, 6, 7, 8, 9, 10
Print(1..^1); // 1..^1 => 2, 3, 4, 5, 6, 7, 8, 9
Print(^2..^1); // ^2..^1 => 9
}
}
} Console.WriteLine("123456789"[1..4]); // Would output 234 var helloWorldStr = "Hello, World!"; var hello = helloWorldStr[..5]; Console.WriteLine(hello); // Output: Hello var world = helloWorldStr[7..]; Console.WriteLine(world); // Output: World! var world2 = helloWorldStr[^6..]; // Take the last 6 characters Console.WriteLine(world); // Output: World!
var arr = (new[] { 1, 4, 8, 11, 19, 31 }).AsSpan();
var range = arr[2..5];
ref int elt1 = ref range[1];
elt1 = -1;
int copiedElement = range[2];
copiedElement = -2;
Console.WriteLine($"range[1]: {range[1]}, range[2]: {range[2]}"); // output: range[1]: -1, range[2]: 19
Console.WriteLine($"arr[3]: {arr[3]}, arr[4]: {arr[4]}"); // output: arr[3]: -1, arr[4]: 19 // ... builder.Services.AddRazorComponents().AddInteractiveServerComponents(); // ... app.MapRazorComponents<App>().AddInteractiveServerRenderMode();
// ... builder.Services.AddRazorComponents(); // ... app.MapRazorComponents<App>();
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<base href="/" />
<link rel="stylesheet" href="bootstrap/bootstrap.min.css" />
<link rel="stylesheet" href="app.css" />
<link rel="stylesheet" href="MyApp.styles.css" />
<link rel="icon" type="image/png" href="favicon.png" />
<HeadOutlet />
</head>
<body>
<Routes />
<script src="_framework/blazor.web.js"></script>
</body>
</html> <Router AppAssembly="@typeof(Program).Assembly">
<Found Context="routeData">
<RouteView RouteData="@routeData" DefaultLayout="@typeof(Layout.MainLayout)" />
<FocusOnNavigate RouteData="@routeData" Selector="h1" />
</Found>
</Router> app.UseStatusCodePagesWithRedirects("/StatusCode/{0}"); @page "/StatusCode/{responseCode}"
<h3>StatusCode @ResponseCode</h3>
@code {
[Parameter] public string? ResponseCode { get; set; }
} if (!app.Environment.IsDevelopment())
{
app.UseExceptionHandler("/Error", createScopeForErrors: true);
} 404.razor
@page "/StatusCode/404" <PageTitle>Not found</PageTitle> <h1>Not found</h1> <p role="alert">Sorry, there's nothing at this address.</p>
500.razor
@page "/StatusCode/500" <PageTitle>Unexpected error</PageTitle> <h1>Unexpected error</h1> <p role="alert">There was an unexpected error.</p>
401.razor
@page "/StatusCode/401" <PageTitle>Not Authorized</PageTitle> <h1>Not Authorized</h1> <p role="alert">Sorry, you are not authorized to access this page.</p>
<HeadOutlet @rendermode="@InteractiveServer" /> ... <Routes @rendermode="@InteractiveServer" />
dotnet new blazor --interactivity Server --all-interactive
@rendermode InteractiveServerRenderModeWithoutPrerendering
@code{
static readonly IComponentRenderMode InteractiveServerRenderModeWithoutPrerendering =
new InteractiveServerRenderMode(false);
} interface ILogger
{
void Log(string message);
}
class ConsoleLogger : ILogger
{
public void Log(string message)
{
Console.WriteLine(message);
}
} interface ILogger
{
void Log(string message);
void Log(Exception exception) => Console.WriteLine(exception);
} interface IDeveloper
{
void LearnNewLanguage(string language, DateTime dueDate);
void LearnNewLanguage(string language)
{
// default implementation
LearnNewLanguage(language, DateTime.Now.AddMonths(6));
}
}
class BackendDev : IDeveloper // compiles OK
{
public void LearnNewLanguage(string language, DateTime dueDate)
{
// Learning new language...
}
} IDeveloper dev1 = new BackendDev();
dev1.LearnNewLanguage("Rust");
var dev2 = new BackendDev();
dev2.LearnNewLanguage("Rust");
There is no argument given that corresponds to the required formal parameter 'dueDate' of 'BackendDev.LearnNewLanguage(string, DateTime)' (CS7036) [ConsoleApp]
using System;
namespace ConsoleApp
{
public interface IDev
{
void LearnNewLanguage(string language) => Console.Write($"Learning {language} in a default way.");
}
public interface IBackendDev : IDev
{
void LearnNewLanguage(string language) => Console.Write($"Learning {language} in a backend way.");
}
public interface IFrontendDev : IDev
{
void LearnNewLanguage(string language) => Console.Write($"Learning {language} in a frontend way.");
}
public interface IFullStackDev : IBackendDev, IFrontendDev { }
public class Dev : IFullStackDev { }
} IFullStackDev dev = new Dev();
dev.LearnNewLanguage("TypeScript"); The call is ambiguous between the following methods or properties: 'IBackendDev.LearnNewLanguage(string)' and 'IFrontendDev.LearnNewLanguage(string)' (CS0121)
namespace MyNamespace
{
public interface IMyInterface
{
IList<int> Values { get; set; }
}
public static class MyInterfaceExtensions
{
public static int CountGreaterThan(this IMyInterface myInterface, int threshold)
{
return myInterface.Values?.Where(p => p > threshold).Count() ?? 0;
}
}
} var myImplementation = new MyInterfaceImplementation(); // Note that there's no typecast to IMyInterface required var countGreaterThanFive = myImplementation.CountGreaterThan(5);
Today, we are releasing .NET 5.0 Preview 8. The .NET 5.0 release is now “feature complete”, meaning that very nearly all features are in their final form (with the exception of bug fixes still to come). Preview 8 is, appropriately, the last preview. We plan on releasing two go-live release candidates before the final .NET 5.0 release in November. This post describes a selection of features across the .NET 5.0 release.
.NET 8 Web API from A to Z
19 videos
