IDisposable.Dispose永远不会在使用块后发生异常后调用 [英] IDisposable.Dispose is never called after exception in using block

问题描述

我从诸如此和此，如果在 IDisposable 中的 Dispose 方法将始终被调用， 使用块。因此，我得到了以下代码：

I understand from many sources like this and this that the Dispose method of an IDisposable will always be called if an exception is thrown in a Using block. So then I have this code:

static class MainEntryPoint
{
    static void Main(string[] args)
    {
        AppDomain.CurrentDomain.UnhandledException += HandleUnhandledException;

        using (var x = new Disposable())
        {
            throw new Exception("asdfsdf");
        }
    }

    private static void HandleUnhandledException(Object sender, System.UnhandledExceptionEventArgs e)
    {
        Environment.Exit(0);
    }
}

class Disposable : IDisposable
{
    public void Dispose()
    {
        System.Diagnostics.Debug.Print("I am disposed");
    }
}

当未处理的异常为抛出。永远不会调用 Dispose 方法。为什么？

It exits the application when an un-handled exception is thrown. The Dispose method is never called. Why?

推荐答案

Environment.Exit 将终止程序

如果从try或catch块中调用Exit，则任何最终
块中的代码都不会执行。如果使用return语句，则
finally块中的代码会执行。

If Exit is called from a try or catch block, the code in any finally block does not execute. If the return statement is used, the code in the finally block does execute.

using (var x = new Disposable())
{
    throw new Exception("asdfsdf");
}

将转换为

Disposable x = new Disposable();
try
{
    throw new Exception("asdfsdf");
}
finally
{
    if (x != null)
        x.Dispose();
}

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