c# - CryptoStream可以使基本Stream保持打开状态吗？

我创建一个MemoryStream，将其传递给CryptoStream进行编写。我希望对CryptoStream进行加密，并让MemoryStream打开供我阅读，然后再阅读其他内容。但是，一旦配置了CryptoStream，它也会配置MemoryStream。
CryptoStream是否可以使基础MemoryStream保持打开状态？

using (MemoryStream scratch = new MemoryStream())
{
    using (AesManaged aes = new AesManaged())
    {
        // <snip>
        // Set some aes parameters, including Key, IV, etc.
        // </snip>
        ICryptoTransform encryptor = aes.CreateEncryptor();
        using (CryptoStream myCryptoStream = new CryptoStream(scratch, encryptor, CryptoStreamMode.Write))
        {
            myCryptoStream.Write(someByteArray, 0, someByteArray.Length);
        }
    }
    // Here, I'm still within the MemoryStream block, so I expect
    // MemoryStream to still be usable.
    scratch.Position = 0;    // Throws ObjectDisposedException
    byte[] scratchBytes = new byte[scratch.Length];
    scratch.Read(scratchBytes,0,scratchBytes.Length);
    return Convert.ToBase64String(scratchBytes);
}

最佳答案

您可以但不能使用using语句。您将需要手动管理对象的处理，还需要调用 FlushFinialBlock() 来确保在处理之前将所有数据写到基础流中。

一旦完成所有工作，就可以将所有资源放在最后的finally块中等待的地方。

MemoryStream scratch = null;
AesManaged aes = null;
CryptoStream myCryptoStream = null;
try
{
    scratch = new MemoryStream();
    aes = new AesManaged();

    // <snip>
    // Set some aes parameters, including Key, IV, etc.
    // </snip>
    ICryptoTransform encryptor = aes.CreateEncryptor();
    myCryptoStream = new CryptoStream(scratch, encryptor, CryptoStreamMode.Write);
    myCryptoStream.Write(someByteArray, 0, someByteArray.Length);

    //Flush the data out so it is fully written to the underlying stream.
    myCryptoStream.FlushFinalBlock();

    scratch.Position = 0;
    byte[] scratchBytes = new byte[scratch.Length];
    scratch.Read(scratchBytes,0,scratchBytes.Length);
    return Convert.ToBase64String(scratchBytes);
}
finally
{
    //Dispose all of the disposeable objects we created in reverse order.

    if(myCryptoStream != null)
        myCryptoStream.Dispose();

    if(aes != null)
        aes.Dispose();

    if(scratch != null)
        scratch.Dispose();
}