Update through ContentService

gistfile1.txt

using System.Configuration;
using System.Web.Mvc;
using Umbraco.Web.Mvc;
using Umbraco.Web.UI.Umbraco.Controls;

namespace My.Controllers
{
    public class MyUpdateController : SurfaceController
    {
        public ActionResult Create(SomeModel model)
        {
            if (!ModelState.IsValid)
                return CurrentUmbracoPage();

            var contentService = Services.ContentService;
            var currentPageId= UmbracoContext.PageId.Value;
            var content = contentService.GetById(currentPageId);
            content.SetValue("myProp", model.MyProp);
            
            contentService.PublishWithStatus(content);
            
            return RedirectToCurrentUmbracoPage();
        }
    }
}