Доработано Demo

Demo/Pages/DetailsPage.cs

@@ -1,27 +1,57 @@
 using BotPages.Core;
 using BotPages.Core.Messaging;
+using System.Xml;
 
 namespace Demo.Pages;
 
 /// <summary>
 /// Страница ввода деталей заявки.
+/// Страница с параметрами и сохранением состояния.
 /// </summary>
 public sealed class DetailsPage : StatefullPage<DetailsArgs>
 {
+    [Statefull("Request")]
+    private Models.Request Request;
+
     public override Task OnEnter(PageContext ctx, DetailsArgs args, CancellationToken ct)
-        => new MessageBuilder(ctx)
+    {
+        Request = new()
+        {
+            Title = args.Title,
+        };
+
+        return new MessageBuilder(ctx)
             .Text($"Заголовок: {args.Title}\nДобавьте детали или нажмите Далее.")
             .Inline(new InlineButton("Далее", "next"), new InlineButton("Назад", "back"))
             .Reply("Отмена")
             .SendAsync(ct);
+    }
 
-    public override Task OnButton(PageContext ctx, string payload, CancellationToken ct)
-        => payload switch
+    public override async Task OnButton(PageContext ctx, string payload, CancellationToken ct)
+    {
+        switch (payload)
         {
-            "next" => ctx.Navigation.GoToAsync<FilesPage>(ctx, ct),
-            "back" => ctx.Navigation.GoToAsync<TitlePage>(ctx, ct),
-            _ => Task.CompletedTask
+            case "next":
+                {
+                    await SaveState(ctx, ct);
+                    await ctx.Navigation.GoToAsync<FilesPage>(ctx, ct);
+                    break;
+                }
+
+            case "back": 
+                {
+                    await ctx.Navigation.GoToAsync<TitlePage>(ctx, ct);
+                    break;
+                }
         };
+    }
+
+    public override async Task OnText(PageContext ctx, string text, CancellationToken ct)
+    {
+        Request.Details = text;
+        await SaveState(ctx, ct);
+        await ctx.Navigation.GoToAsync<FilesPage>(ctx, ct);
+    }
 }
 
 /// <summary>