如何将模型加载到_Layout.cshtml和各种意见之间共享呢？ [英] How to load a Model into _Layout.cshtml and share it among various Views?

问题描述

我有一个MVC4项目以两课的交易。整个应用程序的许多页面需要处理课程的列表 - 用户配置文件需要拉起列表中，/课程索引视图需要拉列表等。

I have an MVC4 project that deals with "Courses". Many pages throughout the app need to deal with a list of Courses - user profiles need to pull up the list, the Index view for /Courses needs to pull the list, etc.

由于这个数据是pretty多少总是需要，我想它加载作为初始请求的一部分，所以我只需要查询数据库一次。

Since this data is pretty much always required, I'd like to load it as part of the initial request, so I only have to query the DB one time.

我想在这里得到的数据放置在Layout.cshtml，然后其他视图可以根据需要访问模型数据，虽然我没有看到实现这一目标的一条明路的情况。我想我可以把问题分解成两部分：

I imagine a scenario where the data gets placed in Layout.cshtml, and then other views can access the Model data as needed, though I don't see a clear way of achieving this. I think I can break the problem into two pieces:

1. 获取加载到Layout.cshtml数据


2. 访问其他意见这个数据

我有点憋屈都 - 我怎样才能使这项工作？

I'm a bit stuck on both - how can I make this work?

推荐答案

您应该使用缓存或的OutputCache ，把这个列表到部分查看，然后渲染它无处不在，你需要：

You should use Cache or OutputCache, put this list into a Partial View, and then render it everywhere you need:

1）创建一个动作来pupulate的部分查看。这种观点将被缓存的最大持续时间，那么任何访问不会产生任何开销：

1) Create an Action to pupulate the Partial View. This view will be cached for max duration time, then any access will not generate any overhead:

[NonAction]
[OutputCache(Duration = int.MaxValue, VaryByParam = "none")]
public ActionResult GetCourses()
{
  List<Course> courses = new List<Course>();

  /*Read DB here and populate the list*/

  return PartialView("_Courses", courses);
}

2）使用 Chache 填充以同样的方式在部分查看：

[NonAction]
public ActionResult GetCourses()
{
  List<Course> courses = new List<Course>();

  if (this.HttpContext.Cache["courses"] == null)
  {
    /*Read DB here and populate the list*/

    this.HttpContext.Cache["courses"] = courses;
  }
  else
  {
    courses = (List<Course>)this.HttpContext.Cache["courses"];
  }

  return PartialView("_Courses", courses);
}

3）渲染这个视图由 Html.Action 或 Html.RenderAction ：

@Html.Action("GetCourses", "ControllerName")

或

@{ Html.RenderAction("GetCourses", "ControllerName"); }

有关缓存

更多信息：<一href=\"http://www.asp.net/mvc/tutorials/older-versions/controllers-and-routing/improving-performance-with-output-caching-cs\">Improving性能输出缓存

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