ASP.Net Core的ViewBag生命周期

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英文:

ASP.Net Core lifecycle of ViewBag

问题

我正在将一个传统的ASP.Net MVC网站转换为Core,我过去常常让所有的控制器都继承自一个BaseController类,该类覆盖了Initialize方法,并在ViewBag上设置了一些属性。现在似乎没有Initialize方法了,所以我通过构造函数来做这个。然而,当我到达操作方法时,似乎ViewBag已经被重置了。

代码基本上是这样的:

public abstract class BaseController : Controller
{
    protected BaseController()
    {
        ViewBag.Hello = "hello";
    }
}

public class MyController : BaseController
{
    public IActionResult Index()
    {
        var hello = ViewBag.Hello;
        // 但hello是null

        return View();
    }
}

我应该覆盖一个不同的方法,而不是通过构造函数吗?ViewBag在哪里被重置,有没有更好的方法来解决这个问题?


您可以尝试使用ASP.NET Core中的OnActionExecuting方法来设置ViewBag属性,而不是通过构造函数。这可以确保在执行操作之前设置ViewBag属性,而不会被重置。

以下是修改后的示例代码:

using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Filters;

public abstract class BaseController : Controller
{
    public override void OnActionExecuting(ActionExecutingContext context)
    {
        base.OnActionExecuting(context);
        ViewBag.Hello = "hello";
    }
}

public class MyController : BaseController
{
    public IActionResult Index()
    {
        var hello = ViewBag.Hello;
        // 现在hello应该包含"hello"的值

        return View();
    }
}

通过覆盖OnActionExecuting方法,您可以确保在执行操作之前设置ViewBag属性,从而避免被重置。这是在ASP.NET Core中更常见的一种方式来处理此类情况。

英文:

I am converting a legacy ASP.Net MVC website to Core, and I used to have all controllers inherit from a BaseController class which was overriding Initialize and setting some properties on the ViewBag. There seems to be no Initialize method now, so I'm doing that through the constructor. However, by the time I get to the Action method, it seems the ViewBag has been reset.

The code is basically like this:

public abstract class BaseController : Controller
{
    protected BaseController()
    {
        ViewBag.Hello = "hello";
    }
}

public class MyController : BaseController
{
    public IActionResult Index()
    {
        var hello = ViewBag.Hello;
        // but hello is null

        return View();
    }
}

Should I be overriding a different method rather than going through the constructor? Where is ViewBag getting reset and what is a better way to work around that?

答案1

得分: 0

尝试重写 OnActionExecuting 方法:

public abstract class BaseController : Controller
{
    //protected BaseController()
    //{
    //    ViewBag.Hello = "hello";
    //}
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        ViewBag.Hello = "hello"

        base.OnActionExecuting(filterContext);
    }
}

结果:

ASP.Net Core的ViewBag生命周期

英文:

Try to override OnActionExecuting method :

public abstract class BaseController : Controller
    {
        //protected BaseController()
        //{
        //    ViewBag.Hello = "hello";
        //}
        public override void OnActionExecuting(ActionExecutingContext filterContext)
        {
            ViewBag.Hello = "hello";
           
            base.OnActionExecuting(filterContext);
        }
    }

result:

ASP.Net Core的ViewBag生命周期

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  • 本文由 发表于 2023年7月3日 18:05:11
  • 转载请务必保留本文链接:https://go.coder-hub.com/76603728.html
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