Blazor-based component generator POC

.editorconfig

@@ -37,5 +37,8 @@ charset = utf-8-bom
 indent_size = 2
 insert_final_newline = false
 
+[*.razor]
+indent_size = 2
+
 [justfile]
 indent_size = 2

samples/Samples.MvcStarter/Program.cs

@@ -1,5 +1,7 @@
 using GovUk.Frontend.AspNetCore;
+using GovUk.Frontend.AspNetCore.Blazor;
 using Joonasw.AspNetCore.SecurityHeaders;
+using Microsoft.AspNetCore.Components.Web;
 
 var builder = WebApplication.CreateBuilder(args);
 
@@ -16,6 +18,9 @@
     //};
 });
 
+builder.Services.AddScoped<HtmlRenderer>();
+builder.Services.AddScoped<BlazorComponentGenerator>();
+
 var app = builder.Build();
 
 // Configure the HTTP request pipeline.

samples/Samples.MvcStarter/Views/Home/Index.cshtml

@@ -1,5 +1,17 @@
-@{
+@using GovUk.Frontend.AspNetCore.Blazor
+@using GovUk.Frontend.AspNetCore.Components
+@inject BlazorComponentGenerator ComponentGenerator
+@{
     ViewBag.Title = "MVC Starter";
 }
 
 <h1 class="govuk-heading-xl">MVC Starter</h1>
+
+@await ComponentGenerator.GenerateWarningTextAsync(new WarningTextOptions()
+{
+    Text = null,
+    Html = "hello world",
+    IconFallbackText = null,
+    Classes = "classes",
+    Attributes = null
+})

src/GovUk.Frontend.AspNetCore/Blazor/BlazorComponentGenerator.cs

@@ -0,0 +1,26 @@
+using GovUk.Frontend.AspNetCore.Components;
+using Microsoft.AspNetCore.Components;
+using Microsoft.AspNetCore.Components.Web;
+using Microsoft.AspNetCore.Html;
+
+namespace GovUk.Frontend.AspNetCore.Blazor;
+
+public class BlazorComponentGenerator(HtmlRenderer htmlRenderer)
+{
+    public async Task<IHtmlContent> GenerateWarningTextAsync(WarningTextOptions options)
+    {
+        ArgumentNullException.ThrowIfNull(options);
+
+        var parameters = ParameterView.FromDictionary(
+            new Dictionary<string, object?>()
+            {
+                { "Options", options }
+            });
+
+        return await htmlRenderer.Dispatcher.InvokeAsync(async () =>
+        {
+            var output = await htmlRenderer.RenderComponentAsync<WarningText>(parameters);
+            return new HtmlString(output.ToHtmlString());
+        });
+    }
+}

src/GovUk.Frontend.AspNetCore/Blazor/WarningText.razor

@@ -0,0 +1,15 @@
+@using System.Text.Encodings.Web
+@using GovUk.Frontend.AspNetCore.Components
+
+@code {
+  [Parameter, EditorRequired] public WarningTextOptions Options { get; set; } = null!;
+}
+
+<div class="govuk-warning-text @(Options.Classes)"
+  @*{{- govukAttributes(params.attributes) }}*@>
+  <span class="govuk-warning-text__icon" aria-hidden="true">!</span>
+  <strong class="govuk-warning-text__text">
+    <span class="govuk-visually-hidden">@(Options.IconFallbackText ?? "Warning")</span>
+    @(Options.Html is not null ? new MarkupString(Options.Html.ToHtmlString(HtmlEncoder.Default)) : Options.Text)
+  </strong>
+</div>