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Async POST with Sitefinity MVC Widgets

by Stanislav Velikov

There are three modes for working with MVC in Sitefinity. The difference is that Sitefinity’s MVC support allows multiple controllers on a Sitefinity page versus classic MVC using only one controller. This may cause problems when a controller performs a postback and navigates to an action.

Example

  • FirstController has actions Index and IndexPostBack
  • SecondController has actions Load and LoadPostBack

Both controllers are placed on a Sitefinity hybrid page, allowing for MVC widgets and WebForms widgets. FirstController performs a postback, which changes the URL to http://site.com/page/IndexPostBack.

SecondController is not rendered on this URL because the action Load is not available for the route http://site.com/page/IndexPostBack.

Solution

To overcome this, I provide a sample of two MVC widgets performing postbacks asynchronously. Refer to the attached sample for the code.

There are two controllers: the first for creating News and the second for creating Events (CreateNewsController and EventsController).

Upon postback, the controllers create Sitefinity Event/News items.

[HttpPost]
        public ActionResult Create(CreateNewsModel model)
        {
            if(ModelState.IsValid)
            {
                var manager = NewsManager.GetManager();
                var newsItem = manager.CreateNewsItem();
                newsItem.Title = model.Title;
                newsItem.Content = model.Content;
                newsItem.Author = model.Author;
                manager.SaveChanges();
 
                Dictionary<string, string> contextBag = new Dictionary<string, string>();
                WorkflowManager.MessageWorkflow(newsItem.Id, typeof(NewsItem), manager.Provider.Name, "Publish", true, contextBag);
 
                return Content(MvcHelper.RenderPartialViewToString(this, "_NewsCreated", null));
            }
 
            return Content(MvcHelper.RenderPartialViewToString(this, "Default", model));
        }

Under normal conditions, the postback redirects to a new route, and in this case, it goes to http://site.com/page/Create. This hides all other widgets since they are unavailable for this route.

The control handles this redirect to another route by performing an async postback. When creating a news/event item, the result of the postback loads two partial views (_NewsCreated.cshtml and _EventCreated.cshtml) through the MvcHelper class.

public class MvcHelper
    {
        public static string RenderPartialViewToString(Controller controller, string viewName, object model)
        {
            if (string.IsNullOrEmpty(viewName))
                viewName = controller.ControllerContext.RouteData.GetRequiredString("action");
 
            controller.ViewData.Model = model;
 
            using (var sw = new StringWriter())
            {
                var viewResult = ViewEngines.Engines.FindPartialView(controller.ControllerContext, viewName);
                var viewContext = new ViewContext(controller.ControllerContext, viewResult.View, controller.ViewData, controller.TempData, sw);
                viewResult.View.Render(viewContext, sw);
 
                return sw.GetStringBuilder().ToString();
            }
        }
    }

The async postback is performed client-side by the script NewsScript/EventScript.js.

//check if Create ActionResult is called
$(document).ready(
    function () {
        $("#createNews").click(
            function(){
                var model = NewsObject.collectModel();
                NewsObject.sendData(model, "/" + CURRENTPAGE + "/Create", "myNewsForm");
            }
        );
    });
 
//perform async POST
    sendData: function(newsData, destination, resultHolderId) {
        $.ajax({
                type: 'POST',
                url: destination,
                contentType: 'application/json; charset=utf-8',
                data: JSON.stringify(newsData),
                success: function (result, args) {
                    $("#"+resultHolderId).html(result)
                },
                error: this._syncFailureDelegate
        });
    }
}

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