由于没有一个答案涉及从一个流复制到另一个流的异步方式，这里是我在端口转发应用程序中成功使用的一种模式，它将数据从一个网络流复制到另一个网络流。它缺乏异常处理来强调模式。

const int BUFFER_SIZE = 4096;

static byte[] bufferForRead = new byte[BUFFER_SIZE];
static byte[] bufferForWrite = new byte[BUFFER_SIZE];

static Stream sourceStream = new MemoryStream();
static Stream destinationStream = new MemoryStream();

static void Main(string[] args)
{
    // Initial read from source stream
    sourceStream.BeginRead(bufferForRead, 0, BUFFER_SIZE, BeginReadCallback, null);
}

private static void BeginReadCallback(IAsyncResult asyncRes)
{
    // Finish reading from source stream
    int bytesRead = sourceStream.EndRead(asyncRes);
    // Make a copy of the buffer as we'll start another read immediately
    Array.Copy(bufferForRead, 0, bufferForWrite, 0, bytesRead);
    // Write copied buffer to destination stream
    destinationStream.BeginWrite(bufferForWrite, 0, bytesRead, BeginWriteCallback, null);
    // Start the next read (looks like async recursion I guess)
    sourceStream.BeginRead(bufferForRead, 0, BUFFER_SIZE, BeginReadCallback, null);
}

private static void BeginWriteCallback(IAsyncResult asyncRes)
{
    // Finish writing to destination stream
    destinationStream.EndWrite(asyncRes);
}

下面的代码可以解决这个问题，使用CopyTo将流复制到MemoryStream

Stream stream = new MemoryStream();

//任何需要输入流的函数。在我的情况下，保存PDF文件为流 document.Save(流);

MemoryStream newMs = (MemoryStream)stream;

byte[] getByte = newMs.ToArray();

//注意-请在finally块中处理流，而不是在using块中处理，因为它会抛出一个错误'访问被拒绝，因为流被关闭'

对于。net 3.5和尝试之前:

MemoryStream1.WriteTo(MemoryStream2);

由于没有一个答案涉及从一个流复制到另一个流的异步方式，这里是我在端口转发应用程序中成功使用的一种模式，它将数据从一个网络流复制到另一个网络流。它缺乏异常处理来强调模式。

const int BUFFER_SIZE = 4096;

static byte[] bufferForRead = new byte[BUFFER_SIZE];
static byte[] bufferForWrite = new byte[BUFFER_SIZE];

static Stream sourceStream = new MemoryStream();
static Stream destinationStream = new MemoryStream();

static void Main(string[] args)
{
    // Initial read from source stream
    sourceStream.BeginRead(bufferForRead, 0, BUFFER_SIZE, BeginReadCallback, null);
}

private static void BeginReadCallback(IAsyncResult asyncRes)
{
    // Finish reading from source stream
    int bytesRead = sourceStream.EndRead(asyncRes);
    // Make a copy of the buffer as we'll start another read immediately
    Array.Copy(bufferForRead, 0, bufferForWrite, 0, bytesRead);
    // Write copied buffer to destination stream
    destinationStream.BeginWrite(bufferForWrite, 0, bytesRead, BeginWriteCallback, null);
    // Start the next read (looks like async recursion I guess)
    sourceStream.BeginRead(bufferForRead, 0, BUFFER_SIZE, BeginReadCallback, null);
}

private static void BeginWriteCallback(IAsyncResult asyncRes)
{
    // Finish writing to destination stream
    destinationStream.EndWrite(asyncRes);
}

简单安全-从原始来源制作新流:

    MemoryStream source = new MemoryStream(byteArray);
    MemoryStream copy = new MemoryStream(byteArray);

如果你想要一个过程复制一个流到其他的一个，尼克张贴是好的，但它是丢失的位置重置，它应该是

public static void CopyStream(Stream input, Stream output)
{
    byte[] buffer = new byte[32768];
    long TempPos = input.Position;
    while (true)    
    {
        int read = input.Read (buffer, 0, buffer.Length);
        if (read <= 0)
            return;
        output.Write (buffer, 0, read);
    }
    input.Position = TempPos;// or you make Position = 0 to set it at the start
}

但如果它在运行时不使用过程，则应该使用内存流

Stream output = new MemoryStream();
byte[] buffer = new byte[32768]; // or you specify the size you want of your buffer
long TempPos = input.Position;
while (true)    
{
    int read = input.Read (buffer, 0, buffer.Length);
    if (read <= 0)
        return;
    output.Write (buffer, 0, read);
 }
    input.Position = TempPos;// or you make Position = 0 to set it at the start