SteveSandersonMS

#include <wasi/api.h>
#include <stdlib.h>

// Based on https://github.com/WebAssembly/wasi-libc/blob/main/libc-bottom-half/sources/__wasilibc_real.c,

int32_t __imported_wasi_snapshot_preview1_args_get(int32_t arg0, int32_t arg1) { return 0; }

int32_t __imported_wasi_snapshot_preview1_args_sizes_get(int32_t arg0, int32_t arg1) { return 0; }

int32_t __imported_wasi_snapshot_preview1_environ_get(int32_t arg0, int32_t arg1) { return 0; }

SteveSandersonMS

@page "/"
@using Microsoft.AspNetCore.Components.QuickGrid

<label>
    <input @bind="@showName" type="checkbox" />
    Show name
</label>

<QuickGrid Items="@people">
    @Columns()

SteveSandersonMS

public static class EventUtil
{
    // The repetition in here is because of the four combinations of handlers (sync/async * with/without arg)
    public static Action AsNonRenderingEventHandler(Action callback)
        => new SyncReceiver(callback).Invoke;
    public static Action<TValue> AsNonRenderingEventHandler<TValue>(Action<TValue> callback)
        => new SyncReceiver<TValue>(callback).Invoke;
    public static Func<Task> AsNonRenderingEventHandler(Func<Task> callback)
        => new AsyncReceiver(callback).Invoke;
    public static Func<TValue, Task> AsNonRenderingEventHandler<TValue>(Func<TValue, Task> callback)

SteveSandersonMS

using System;
using System.Threading.Tasks;

namespace Microsoft.AspNetCore.Components
{
    public class SectionContent : IComponent, IDisposable
    {
        private SectionRegistry _registry;

        [Parameter] public string Name { get; set; }

SteveSandersonMS

@page "/"
@using System.Net.WebSockets
@using System.Text
@using System.Threading
@implements IDisposable

<h1>Echo test</h1>
<h3>State: @webSocket.State</h3>

@if (webSocket.State == WebSocketState.Open)

SteveSandersonMS

console.log('Hello, world!');

SteveSandersonMS

public class Customer
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public Address Address { get; } = new Address();
    public List<PaymentMethod> PaymentMethods { get; } = new List<PaymentMethod>();
}

public class Address
{

SteveSandersonMS

@page "/"

<h1>Hello, world!</h1>

Welcome to your new app.

<EditForm Model="@_editingPerson" OnValidSubmit="@OnValidSubmit" OnInvalidSubmit="@OnInvalidSubmit">
    <p>
        Name: <InputText @bind-Value="_editingPerson.Name" />
        <ValidationMessage For="@(() => _editingPerson.Name)" />

SteveSandersonMS

Error handling in Server-Side Blazor

Developers building Blazor applications should be aware of how the framework deals with exceptions, and what steps to take in order to maximize reliability and to detect and diagnose errors.

To recap, server-side Blazor is a stateful framework. For as long as users are interacting with your application, they maintain a connection to the server known as a circuit. The circuit holds all the active component instances, plus many other aspects of state such as the components' most recent render output and the current set of event-handling delegates that could be triggered by client-side events. If a user opens your application in multiple browser tabs, then they have multiple independent circuits.

As a high-level principle, Blazor treats most unhandled exceptions as fatal to that circuit. If a circuit is terminated due to an unhandled exception, the user can only continue by reloading the page to create a new circuit and starting again, although other circuits (e.g., th

SteveSandersonMS

Preserving State in Server-Side Blazor applications

Server-side Blazor is a stateful application framework. Most of the time, your users will maintain an ongoing connection to the server, and their state will be held in the server's memory in what's known as a "circuit". Examples of state held for a user's circuit include:

• The UI being rendered (i.e., the hierarchy of component instances and their most recent render output)
• The values of any fields and properties in component instances
• Data held in DI service instances that are scoped to the circuit

Occasionally, users may experience a temporary network connection loss, after which Blazor will attempt to reconnect them to their original circuit so they can continue.