var manager = context.OwinContext.GetUserManager<TManager>();

app.CreatePerOwinContext(() => (ApplicationUserManager)container.GetInstance<IApplicationUserManager>());

var dbContext = HttpContext.GetOwinContext().Get<ApplicationDbContext>();

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">

<script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" integrity="sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" crossorigin="anonymous"></script>

{
  "name": "bootstrap.4",
  "version": "1.0.0",
  "description": "client side resources of the project",
  "scripts": {},
  "author": "VahidN",
  "license": "ISC",
  "dependencies": {
    "bootstrap": "^4.1.3",
    "components-font-awesome": "5.0.6",
    "jquery": "^3.3.1",
    "popper.js": "^1.14.4"
  }
}

Here’s a summary of what’s new in this preview release:

• ASP.NET Core support for native AOT
• Server-side rendering with Blazor
• Render Razor components outside of ASP.NET Core
• Sections support in Blazor
• Monitor Blazor Server circuit activity
• SIMD enabled by default for Blazor WebAssembly apps
• Request timeouts
• Short circuit routes 

Here’s a summary of what’s new in this preview release:

• HTTP/2 performance improvements
• Typed results for minimal APIs
• OpenAPI improvements for minimal APIs
• Return multiple results types from minimal APIs
• Route groups
• Client results in SignalR
• gRPC JSON transcoding
• Project template option to use Program.Main method instead of top-level statements
• Rate limiting middleware 

Here’s a summary of what’s new in this preview release:

• Support for route handler filters in minimal APIs
• Improved unit testability for minimal route handlers
• Bind using TryParse in MVC and API controllers
• New Results.Stream() overloads
• Improved HTTP/2 performance when using many streams on a connection
• New ServerReady event for measuring startup time
• Developer exception page dark mode 

Today, we are releasing React 17! We’ve written at length about the role of the React 17 release and the changes it contains in the React 17 RC blog post. This post is a brief summary of it, so if you’ve already read the RC post, you can skip this one. 

namespace BlazorTreeView.ViewModels;

public class Comment
{
    public IList<Comment> Comments = new List<Comment>();
    public string? Text { set; get; }
}

using BlazorTreeView.ViewModels;

namespace BlazorTreeView.Pages;

public partial class TreeView
{
    private IReadOnlyDictionary<string, object> ChildrenHtmlAttributes { get; } =
        new Dictionary<string, object>(StringComparer.Ordinal)
        {
            { "style", "list-style: none;" },
        };

    private IList<Comment> Comments { get; } =
        new List<Comment>
        {
            new()
            {
                Text = "پاسخ یک",
            },
            new()
            {
                Text = "پاسخ دو",
                Comments =
                    new List<Comment>
                    {
                        new()
                        {
                            Text = "پاسخ اول به پاسخ دو",
                            Comments =
                                new List<Comment>
                                {
                                    new()
                                    {
                                        Text = "پاسخی به پاسخ اول پاسخ دو",
                                    },
                                },
                        },
                        new()
                        {
                            Text = "پاسخ دوم به پاسخ دو",
                        },
                    },
            },
            new()
            {
                Text = "پاسخ سوم",
            },
        };
}

/// <summary>
///   A custom DntTreeView
/// </summary>
public partial class DntTreeView<TRecord>
{

    /// <summary>
    ///     The treeview's self-referencing items
    /// </summary>
    [Parameter]
    public IEnumerable<TRecord>? Items { set; get; }

    /// <summary>
    ///     The treeview item's template
    /// </summary>
    [Parameter]
    public RenderFragment<TRecord>? ItemTemplate { set; get; }

    /// <summary>
    ///     The content displayed if the list is empty
    /// </summary>
    [Parameter]
    public RenderFragment? EmptyContentTemplate { set; get; }

public class Comment
{
    public IList<Comment> Comments = new List<Comment>();
    public string? Text { set; get; }
}

    /// <summary>
    ///     The property which returns the children items
    /// </summary>
    [Parameter]
    public Expression<Func<TRecord, IEnumerable<TRecord>>>? ChildrenSelector { set; get; }

        <DntTreeView
            TRecord="Comment"
            Items="Comments"
            ChildrenSelector="m => m.Comments"

public partial class DntTreeView<TRecord>
{
    private Expression? _lastCompiledExpression;
    internal Func<TRecord, IEnumerable<TRecord>>? CompiledChildrenSelector { private set; get; }

    // ...

    protected override void OnParametersSet()
    {
        if (_lastCompiledExpression != ChildrenSelector)
        {
            CompiledChildrenSelector = ChildrenSelector?.Compile();
            _lastCompiledExpression = ChildrenSelector;
        }
    }
}

@namespace BlazorTreeView.Pages.Components
@typeparam TRecord

@if (Items is null || !Items.Any())
{
    @EmptyContentTemplate
}
else
{
    <CascadingValue Value="this">
        <ul @attributes="AdditionalAttributes">
            @foreach (var item in Items)
            {
                <DntTreeViewChildrenItem TRecord="TRecord" ParentItem="item"/>
            }
        </ul>
    </CascadingValue>
}

@namespace BlazorTreeView.Pages.Components
@typeparam TRecord

<li @attributes="@SafeOwnerTreeView.ChildrenHtmlAttributes" @key="ParentItem?.GetHashCode()">
    @if (SafeOwnerTreeView.ItemTemplate is not null && ParentItem is not null)
    {
        @SafeOwnerTreeView.ItemTemplate(ParentItem)
    }
    @if (Children is not null)
    {
        <ul>
            @foreach (var item in Children)
            {
                <DntTreeViewChildrenItem TRecord="TRecord" ParentItem="item"/>
            }
        </ul>
    }
</li>

/// <summary>
///     A custom DntTreeView
/// </summary>
public partial class DntTreeViewChildrenItem<TRecord>
{
    /// <summary>
    ///     Defines the owner of this component.
    /// </summary>
    [CascadingParameter]
    public DntTreeView<TRecord>? OwnerTreeView { get; set; }

    private DntTreeView<TRecord> SafeOwnerTreeView =>
        OwnerTreeView ??
        throw new InvalidOperationException("`DntTreeViewChildrenItem` should be placed inside of a `DntTreeView`.");

    /// <summary>
    ///     Nested parent item to display
    /// </summary>
    [Parameter]
    public TRecord? ParentItem { set; get; }

    private IEnumerable<TRecord>? Children =>
        ParentItem is null || SafeOwnerTreeView.CompiledChildrenSelector is null
            ? null
            : SafeOwnerTreeView.CompiledChildrenSelector(ParentItem);
}

<div class="card" dir="rtl">
    <div class="card-header">
        DntTreeView
    </div>
    <div class="card-body">
        <DntTreeView
            TRecord="Comment"
            Items="Comments"
            ChildrenSelector="m => m.Comments"
            style="list-style: none;"
            ChildrenHtmlAttributes="ChildrenHtmlAttributes">
            <ItemTemplate Context="record">
                <div class="card mb-1">
                    <div class="card-body">
                        <span>@record.Text</span>
                    </div>
                </div>
            </ItemTemplate>
            <EmptyContentTemplate>
                <div class="alert alert-warning">
                    There is no item to display!
                </div>
            </EmptyContentTemplate>
        </DntTreeView>
    </div>
</div>

public class Student
{
    [JsonPropertyName("id")]
    public int Id { get; set; }

    [JsonPropertyName("name")]
    public string Name { get; set; }
}

public class WeatherForecast
{
    [Required]
    public int TemperatureC { get; set; }

    [MinLength(50)]
    public string Summary { get; set; }
}

[AttributeUsage(AttributeTargets.Class)]
public class CustomDoNothingAttribute: Attribute
{
    // Note the type parameter in the constructor
    public CustomDoNothingAttribute(Type t)
    {
        ParamType = t;
    }

    public Type ParamType { get; }
}

[CustomDoNothing(typeof(string))]
public class Student
{
    public int Id { get; set; }

    public string Name { get; set; }
}

[AttributeUsage(AttributeTargets.Class)]
public class CustomDoNothingAttribute<T> : Attribute
    where T : class
{
    public T ParamType { get; }
}

[CustomDoNothing<string>]
public class Student
{
    public int Id { get; set; }

    public string Name { get; set; }
}

[AttributeUsage(AttributeTargets.Class, AllowMultiple = true)]
public class DecorateAttribute<T> : Attribute where T : class
{
    // ....
}

[Decorate<LoggerDecorator>]
[Decorate<TimerDecorator>]
public class SimpleWorker
{
    // ....
}

public class GenericAttribute<T> : Attribute { }

public class GenericType<T>
{
    [GenericAttribute<T>] // Not allowed! generic attributes must be fully constructed types.
    public string Method1() => default;

    [GenericAttribute<string>]
    public string Method2() => default;
}