Transform partial view into string with calling controller's action

Question

I have MVC controller with action that returns partial view. Action contains a lot of logic and sends data in view through ViewBag object.

I need to render result of this action into string and then send as email. All solutions that I found render view without action calling.

Is it possible to init controller somewhere in my code, call action method and transform ActionResult (that is partial view) into string?

Thx

If you are using this for emails you may want to look into something like [MvcMailer](https://www.nuget.org/packages/MvcMailer) which pretty much does what you are looking for. I have had success with it in the past and it is easy to implement. — zgood, Mar 29 '16 at 14:52

score 0 · Accepted Answer · edited May 23 '17 at 12:07

I did it. With a lot of pain.

At first we need to init controller without context. For this I use Rick Strahl's method called CreateController

 public static T CreateController<T>(RouteData routeData = null)
        where T : Controller, new()
    {
        // create a disconnected controller instance
        T controller = new T();

        // get context wrapper from HttpContext if available
        HttpContextBase wrapper = null;
        if (HttpContext.Current != null)
            wrapper = new HttpContextWrapper(System.Web.HttpContext.Current);
        else
            throw new InvalidOperationException(
                "Can't create Controller Context if no active HttpContext instance is available.");

        if (routeData == null)
            routeData = new RouteData();

        // add the controller routing if not existing
        if (!routeData.Values.ContainsKey("controller") && !routeData.Values.ContainsKey("Controller"))
            routeData.Values.Add("controller", controller.GetType().Name
                                                        .ToLower()
                                                        .Replace("controller", ""));

        controller.ControllerContext = new ControllerContext(wrapper, routeData, controller);
        return controller;
    }

Source: http://weblog.west-wind.com/posts/2013/Jul/15/Rendering-ASPNET-MVC-Razor-Views-outside-of-MVC-revisited

But if you call this method when HttpContext it will throw exception. To prevent I init fake context using this code: https://stackoverflow.com/a/19709225/1850880.

Then I init controller and call action. Result of this action contain viewData with all data passed from action. We can get it with reflection (like a ninja). And then we can render view to string with passed model.

        var controller = CreateController<ControllerName>();
        var result = controller.ActionName(param1, param2);
        object viewData = result.GetType().GetProperty("ViewData").GetValue(result);
        object values = viewData.GetType().GetProperty("Values").GetValue(viewData);
        var str = ec.RenderRazorViewToString("ViewName", values);
        return str;

This method render view to string:

 public static string RenderRazorViewToString(this Controller controller, string viewName, object model)
    {
        controller.ViewData.Model = model;
        controller.ViewBag.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);
            viewResult.ViewEngine.ReleaseView(controller.ControllerContext, viewResult.View);
            return sw.GetStringBuilder().ToString();
        }
    }

Looks like it's not the best way but it works. So if you have any ideas be sure to write.

Transform partial view into string with calling controller's action

1 Answers1