Blazor ThemeService

1. Open Program.cs file(s) and register the CookieThemeService:

builder.Services.AddRadzenCookieThemeService(options =>
{
    options.Name = "MyApplicationTheme"; // The name of the cookie
    options.Duration = TimeSpan.FromDays(365); // The duration of the cookie
});

2. Open MainLayout.razor and inject the CookieThemeService:

@inject CookieThemeService CookieThemeService

3. Open the App.razor file of your application and add this code:

@code {
    [CascadingParameter]
    private HttpContext HttpContext { get; set; }

    [Inject]
    private ThemeService ThemeService { get; set; }
    
    [Inject]
    private IOptions<CookieThemeServiceOptions> Options { get; set; }

    protected override void OnInitialized()
    {
        base.OnInitialized();

        if (HttpContext != null)
        {
            var theme = HttpContext.Request.Cookies["MyApplicationTheme"];

            if (!string.IsNullOrEmpty(theme))
            {
                ThemeService.SetTheme(theme, false);
            }
            else
            {
                HttpContext.Response.Cookies.Append("MyApplicationTheme", "material" , new CookieOptions { Secure = Options.Value.IsSecure, Expires = DateTimeOffset.Now.Add(Options.Value.Duration) });    
            }
        }
    }
}