为什么我的FileStream对象被设置的时候，我和QUOT的;使用＆QUOT; BinaryReader在一个对象？ [英] Why is my FileStream object being disposed of when I'm "using" a BinaryReader object?

问题描述

考虑下面的函数：

    private int GetSomethingFromFile(FileStream fs) 
    {
        using (BinaryReader br = new BinaryReader(fs))
        {
            fs.Seek(0, SeekOrigin.Begin);
            return br.ReadInt32();
        }
    }

一个FileStream对象传入作为参数，BinaryReader在一个与using语句声明。当我尝试使用FileStream对象，调用此函数后，它抛出一个System.ObjectDisposedException。这是为什么FileStream对象被设置的一起物体BinaryReader在？

A FileStream object is passed in as a parameter and a BinaryReader is declared with a using statement. When I try to use that FileStream object, after calling this function, it throws a System.ObjectDisposedException. Why is that FileStream object being disposed of along with the BinaryReader object?

推荐答案

这是一个很好的问题，我不知道为什么就决定，这是应该的，但很可惜它被证明是这样的方式：

It is a very good question, and I don't know why it was decided that this was how it should be, but alas it is documented to be this way:

BinaryReader在类

BinaryReader class

关闭：关闭当前读者的和底层流

如果你看看这个答案这个问题我如何叉在.NET中的流？ 那么你会发现他是指一类在一个名为 MiscUtil 该库被称为NonClosingStreamWrapper @ 乔恩斯基特写，你可以用周围的流换到prevent它被封闭。

If you check out this answer to the question How do I "fork" a Stream in .NET? then you'll see that he refers to a class called NonClosingStreamWrapper in a library called MiscUtil that @Jon Skeet has written that you can use to wrap around the stream to prevent it from being closed.

您会使用这样的（对于你的例子）：

You would use it like this (for your example):

private int GetSomethingFromFile(FileStream fs) 
{
    using (var wrapper = new NonClosingStreamWrapper(fs))
    using (BinaryReader br = new BinaryReader(wrapper))
    {
        fs.Seek(0, SeekOrigin.Begin);
        return br.ReadInt32();
    }
}

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