ASP.NET MVC中 在controller 里将 Partial View 转化为字符串的方法

namespace Common.Helper
{
    public static class ControllerExtension
    {
        //根据部分视图名称，把部分视图内容转换成字符串
        public static string RenderPartialViewToString(this Controller controller, string partialViewName)
        {
            return controller.RenderPartialViewToString(partialViewName, null);
        }

        //根据部分视图名称和model，把部分视图内容转换成字符串
        public static string RenderPartialViewToString(this Controller controller, string partialViewName, object model)
        {
            //如果partialViewName为空,就把action名称作为部分视图名称
            if (string.IsNullOrEmpty(partialViewName))
            {
                partialViewName = controller.ControllerContext.RouteData.GetRequiredString("action");
            }

            //把model放到Controller.ViewData.Model属性中
            controller.ViewData.Model = model;

            using (var sw = new StringWriter())
            {
                //通过视图引擎，在当前ControllerContext中，根据部分视图名称获取ViewEngineResult类型
                var viewResult = ViewEngines.Engines.FindPartialView(controller.ControllerContext, partialViewName);

                //创建ViewContext
                var viewContext = new ViewContext(controller.ControllerContext, viewResult.View, controller.ViewData,
                    controller.TempData, sw);

                //把内容写到StringWriter中
                viewResult.View.Render(viewContext, sw);

                //StringWriter→string
                return sw.GetStringBuilder().ToString();
            }
        }
    }
}