为什么不能赶上的MissingMethodException？ [英] Why is it not possible to catch MissingMethodException?

问题描述

我在.NET 2.0 SP2在我的ClickOnce部署的应用程序的依赖 （在 ApplicationDeployment.CurrentDeployment.CheckForDetailedUpdate（假）方法是SP2只）。

I have a dependency on .NET 2.0 SP2 in my ClickOnce deployed application (the ApplicationDeployment.CurrentDeployment.CheckForDetailedUpdate(false) method is SP2 only).

我想检查SP2是否是在应用程序启动时present。我曾尝试通过调用SP2的唯一方法后赶上的MissingMethodException检测到这一点。

I would like to check whether SP2 is present during app startup. I have tried to detect this by catching MissingMethodException after calling a SP2-only method.

    /// <summary>
    /// The SP2 bootstrapper does not allow HomeSite installation
    /// http://msdn.microsoft.com/en-us/vstudio/bb898654.aspx
    /// So we only advice the user to download .NET 2.0 SP2 manually.
    /// </summary>
    private void CheckDotNet2SP()
    {
        WaitHandle wh = new AutoResetEvent(true);
        try
        {
            wh.WaitOne(1); //this method is .NET 2.0 SP2 only
        }
        //NOTE: this catch does not catch the MissingMethodException
        catch (Exception) //change to catch(MissingMethodException) does not help
        {
            //report that .NET 2.0 SP2 is missing
        }
        finally
        {
            wh.Close();
        }
    }

在code在追赶从未执行时，这个运行在.NET 2.0没有SP2。唯一的例外是只抓到了 AppDomain.CurrentDomain.UnhandledException 事件处理程序。

这怎么可能是的MissingMethodException不抓？我可以想像，这是一个特例 - 在CLR打一个不存在的方法，并不知它是不可能把它传递给catch块。我想了解这背后的原理。

How is it possible that the MissingMethodException is not caught? I can imagine that this is a special case - the CLR hits a method that does not exist and somehow it is not possible to pass this to the catch block. I would like to understand the principle behind this.

任何人有任何关于此问题的资源？是否有不能被捕获在catch块中的任何其他异常？

Anyone has any resources on this issue? Are there any other exceptions that cannot be caught in a catch block?

推荐答案

我怀疑这是发生在JIT时，该方法是正确的，甚至进入前 - 即在你的catch块击中。它的可能的，如果你赶上的MissingMethodException 在呼叫的方法，将梳理出来......特别是如果你装饰 CheckDotNet2SP 与 MethodImpl [MethodImplOptions.NoInlining] 。它仍然听起来就像将pretty的冒险，但。

I suspect it's happening at JIT time, before the method is even properly entered - i.e. before your catch block is hit. It's possible that if you catch MissingMethodException in the calling method, that will sort it out... particularly if you decorate CheckDotNet2SP with MethodImpl[MethodImplOptions.NoInlining]. It still sounds like it would be pretty dicey though.

您可以随时检查的方法与反思的presence而不是试图尽管调用它。

You could always check for the presence of the method with reflection rather than by trying to call it though.

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