Rendering Asp.Net WebForm via an MVC action

As part of our rewrite of WebForms to MVC we have some reports that are generated via Infragistics. I know I said in the previous post that the reason we're doing the rewrite is because we hate Infragistics. However, one thing that Infragistics does well is to give a lot of power to the developer for developing reports.

There is no GUI for report development and the documentation is virtually non existent, but if you need dynamic reports that are generated at run time it's a great library to use.

I won't bore you with implementation details for our reports, but the fact of the matter is that we need to render a WebForm. How do you do that inside a Controller action? Well fortunately the folks at Microsoft have thought of this scenario. There is an IView implementation called WebFormView. So if you need to return a classic Asp.Net Web Form as part of your action, you can do it like so.

public ActionResult Index()
{
   return View(new WebFormView("~/path/to/your/webform.aspx"));
}

The only catch is that your WebForm, must inherit from System.Web.Mvc.ViewPage, rather than System.Web.UI.Page. Behind the scenes it will call the BuildManager to build your web form and call the ProcessRequest method with HttpContext.Current. This means that the page is taken through the Asp.Net page life cycle.

You can even serve up WebControls like this. Again they have to inherit from System.Web.Mvc.ViewUserControl. There is one more limitation. That is that the user control can either only have html elements (albeit they can have the runat=server attribute). Or if you really need server controls, then the user control must contain a form with the runat=server attribute.

One final note. If for whatever reason you cannot change your web forms to inherit from ViewPage or you need to access the compiled instance of the Page, you can still use them to render content inside a controller action like so

public ActionResult Index()
{
   var page = BuildManager
.CreateInstanceFromVirtualPath("~/path/to/your/webform.aspx", typeof(Page));
   page.ProcessRequest(HttpContext.Current);
   return new EmptyResult();
}