ASP.NET - Load a partial from controller code

Partials are a nice way in ASP.NET of sharing mark-up across views. These are usually rendered from within view markup, but sometimes you may want to render a partial from within a controller method - for example if you want to create an HTML email but don’t want to put your HTML into your C# code.

This is easily done using your existing controller context. Assume controller below is a class inheriting from System.Web.Mvc.Controller:

public const string MyViewName = "_MyViewName";

public string LoadPartialHtml(Controller controller, string viewName)
{
    using (var sw = new StringWriter())
    {
        var viewResult = ViewEngines.Engines.FindPartialView(controller.ControllerContext, MyViewName);
        var viewContext = new ViewContext(controller.ControllerContext, viewResult.View, controller.ViewData, controller.TempData, sw);
        viewResult.View.Render(viewContext, sw);
        return sw.ToString();
    }
}