有没有办法在不关闭其 BaseStream 的情况下关闭 StreamWriter?

问题描述

我的根本问题是，当 using 在 StreamWriter 上调用 Dispose 时，它也会处理 BaseStream (Close 也有同样的问题).

My root problem is that when using calls Dispose on a StreamWriter, it also disposes the BaseStream (same problem with Close).

我有一个解决方法，但如您所见，它涉及复制流.有没有办法在不复制流的情况下做到这一点?

I have a workaround for this, but as you can see, it involves copying the stream. Is there any way to do this without copying the stream?

这样做的目的是将一个字符串的内容(最初是从数据库中读取的)获取到一个流中，以便第三方组件可以读取该流.
注意:我无法更改第三方组件.

The purpose of this is to get the contents of a string (originally read from a database) into a stream, so the stream can be read by a third party component.
NB: I cannot change the third party component.

public System.IO.Stream CreateStream(string value)
{
    var baseStream = new System.IO.MemoryStream();
    var baseCopy = new System.IO.MemoryStream();
    using (var writer = new System.IO.StreamWriter(baseStream, System.Text.Encoding.UTF8))
    {
        writer.Write(value);
        writer.Flush();
        baseStream.WriteTo(baseCopy); 
    }
    baseCopy.Seek(0, System.IO.SeekOrigin.Begin);
    return baseCopy;
}

用作

public void Noddy()
{
    System.IO.Stream myStream = CreateStream("The contents of this string are unimportant");
    My3rdPartyComponent.ReadFromStream(myStream);
}

理想情况下，我正在寻找一种名为 BreakAssociationWithBaseStream 的虚构方法，例如

Ideally I'm looking for an imaginary method called BreakAssociationWithBaseStream, e.g.

public System.IO.Stream CreateStream_Alternate(string value)
{
    var baseStream = new System.IO.MemoryStream();
    using (var writer = new System.IO.StreamWriter(baseStream, System.Text.Encoding.UTF8))
    {
        writer.Write(value);
        writer.Flush();
        writer.BreakAssociationWithBaseStream();
    }
    return baseStream;
}

推荐答案

如果您使用的是 .NET Framework 4.5 或更高版本，则有一个 StreamWriter 重载使用它您可以在编写器关闭时要求基本流保持打开状态.

If you are using .NET Framework 4.5 or later, there is a StreamWriter overload using which you can ask the base stream to be left open when the writer is closed.

在 .NET Framework 4.5 之前的早期版本中，StreamWriter 假定它拥有流.选项:

In earlier versions of .NET Framework prior to 4.5, StreamWriter assumes it owns the stream. Options:

• 不要处理StreamWriter；只需冲洗它.
• 创建一个流包装器，它忽略对 Close/Dispose 的调用，但代理其他所有内容.如果你想从那里获取它，我在 MiscUtil 中有一个实现.莉>

• Don't dispose the StreamWriter; just flush it.
• Create a stream wrapper which ignores calls to Close/Dispose but proxies everything else along. I have an implementation of that in MiscUtil, if you want to grab it from there.

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