Try this
 public static string GetTemplateContentInstance(ControllerContext controllerContext, string viewName, object model)
    {
        if (string.IsNullOrWhiteSpace(viewName))
            //Return name of view for current action
            viewName = controllerContext.RouteData.GetRequiredString("action");
        controllerContext.Controller.ViewData.Model = model;
        using (StringWriter stringWriter = new StringWriter())
        {
            ViewEngineResult viewResult = ViewEngines.Engines.FindPartialView(controllerContext, viewName);
            ViewContext viewContext = new ViewContext(controllerContext, viewResult.View, controllerContext.Controller.ViewData, controllerContext.Controller.TempData, stringWriter);
            viewResult.View.Render(viewContext, stringWriter);
            return stringWriter.GetStringBuilder().ToString();
        }
    }
Use as below 
 string viewBody = GetTemplateContentInstance(this.ControllerContext, Url.Content("ViewName"), ModelName)