AugusteVN.Razor.StateChange 1.1.0

StateChangeProvider

Notify whenever the value of a property in our Blazor global state changes.

Usage

Inheritance only.

public class BlogHttpClient : StateChangeProvider
{
    private BlogPostResponse? _selectedBlogPost;
    public BlogPostResponse? SelectedBlogPost {
        get => _selectedBlogPost;
        set => SetField(ref _selectedBlogPost, value);
    }
    
    private readonly HttpClient _http;
    public BlogHttpClient(HttpClient http)
    {
        _http = http;
    }
    
    public async Task InitSelectedBlogPost(GetBlogPostForSlugRequest request)
    {
        SelectedBlogPost = await GetBlogPostForSlug(request);
    }

    private async Task<BlogPostResponse?> GetBlogPostForSlug(GetBlogPostForSlugRequest request)
    {
        try
        {
            return await _http.GetFromJsonAsync<BlogPostResponse>($"{ApiRoutes.BlogPosts}/{request.Slug}");
        }
        catch (Exception e)
        {
            _logger.LogWarning("Could not get blog post with slug: {slug}, {@errorMessage}", request.Slug, e.Message);
            return null;
        }
    }
    
}

Manual Notification

public class BlogHttpClient : StateChangeProvider
{
    private BlogPostResponse? _selectedBlogPost;
    public BlogPostResponse? SelectedBlogPost {
        get => _selectedBlogPost;
        set => SetField(ref _selectedBlogPost, value);
    }
    
    public void UpdateBlogPost(BlogPostResponse blogPost) {
        SelectedBlogPost = new BlogPostResponse { ... }; // Should trigger change notification.
        // But
        SelectedBlogPost.Authors = new List<Author> {...}; // Might not trigger due to nesting etc.
        // So trigger manually.
        NotifyPropertyChanged(nameof(SelectedBlogPost));
    }
}

Property Change Notifications

ExampleComponent.razor

@implements IDisposable
@inject BlogHttpClient BlogHttpClient

@code {
    protected override void OnInitialized()
    {
        BlogHttpClient.PropertyChanged += HandleStateChanged;
    }

    private void HandleStateChanged(object? sender, PropertyChangedEventArgs e)
    {
        if (e.PropertyName == nameof(BlogHttpClient.SelectedBlogPost))
        {
            Console.WriteLine(BlogHttpClient.SelectedBlogPost.Title);
        }
    }

    public void Dispose()
    {
        State.PropertyChanged -= HandleStateChanged;
    }
}

To see it in action, watch: Event-Driven Programming with Blazor in C# .NET 8.

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