在MVC中Http Post之后渲染相同的视图

Question

试图重新发布一个视图,但我得到null我想要的字段.

继承人控制器......

    public ActionResult Upload()
    {
        VMTest vm = new VMTest();
        return View(vm);
    }

    [HttpPost]
    public ActionResult Upload(VMTest vm, String submitButton)
    {
        if (submitButton == "Upload")
        {
            //do some processing and render the same view
            vm.FileName = "2222";           // dynamic creation of filename
            vm.File.SaveAs(@vm.FileName);   // save file to server
            return View(vm);
        }
        else if (submitButton == "Save")
        {
            //read the file from the server
            FileHelperEngine engine = new FileHelperEngine(typeof(PaymentUploadFile));
            PaymentUploadFile[] payments = (PaymentUploadFile[])engine.ReadFile(@vm.FileName);  // the problem lays here @vm.FileName has no value during upload

            //save the record of the file to db
            return View("Success");
        }
        else
        {
            return View("Error");
        }
    }

我的视图中已经有了一个@ Html.HiddenFor(model => Model.FileName).

但我仍然得到Model.FileName的空值.

任何帮助请

谢谢

Answer 1

如果您打算在POST操作中修改视图模型的某些值,则需要先从modelstate中删除旧值:

ModelState.Remove("FileName");
vm.FileName = "2222"; 

原因是TextBox,Hidden,...等Html帮助器在绑定时首先使用modelstate中的值,然后在视图模型中使用值.

而不是:

@Html.HiddenFor(model => Model.FileName)

你应该使用:

@Html.HiddenFor(model => model.FileName)

注意m表达式中的小写.