MVC 5 asp.net，从控制器到视图的viewbag无法正常工作

Question

这是控制器

public ActionResult Test() {

@ViewBag.TheMessageIs = "this is the message";
return RedirectToAction("Details", new { id = theId});

} 

在Action Named Details的视图中 ，我将检查它是否有ViewBag来显示和显示它：

@{
  if(ViewBag.TheMessageIs != null){
         @ViewBag.TheMessageIs
  }
}

但是这里的重定向工作正常，它没有显示我存储在ViewBag中的消息.MessageIs

谢谢

Answer 1

基本上你正在做的是从你的Index方法调用方法Details ，因为你已经用id重载了你的Details动作，所以也传递消息：

public ActionResult Index()
{
    //ViewBag.TheMessageIs = "this is the message";
    return RedirectToAction("Details", new { id = 1, TheMessageIs = "this is the message" });
}

public ActionResult Details(int id, string TheMessageIs)
{
    ViewBag.TheMessageIs = TheMessageIs;
    return View();
}

然后在Details视图中，您可以像这样访问该属性：

@ViewBag.TheMessageIs

Answer 2

public ActionResult Test() {
 TempData["shortMessage"] = "MyMessage";
 return RedirectToAction("Details", new { id = theId});
}

public ActionResult Details {
 //now I can populate my ViewBag (if I want to) with the TempData["shortMessage"] content
  ViewBag.TheMessageIs = TempData["shortMessage"].ToString();
  return View();
}

您必须这样做，因为当您重定向到另一个活动/视图时，viewbag会丢失其值