@model int
@inject IHttpContextAccessor HttpContextAccessor
@inject IDataContextFactory<SeniorDataContext> dbFactory
@using LinqToDB;

@{
    ViewBag.Title = "Hello Razor";
    string username = HttpContextAccessor.HttpContext.Session.GetString("username");
    var db = dbFactory.Create();
    var message = (from m in db.Messages
                    where m.Id.Equals(Model) && m.Reciver.Equals(username)
                    select m).ToArray().FirstOrDefault();
}

<div class="content">
    @if (message == null)
    {
        <p class="text-red">Non hai il permesso</p>
    }
    else
    {
        message.Seen = true;
        db.Update(message);
        <p>Messaggio da @message.Username</p>
        <p>Inviato il @message.Time</p>
        <div class="info-box-text">
            @message.Body
        </div>
    }
</div>