由网友(久居你心)分享简介：我刚刚开始在VB.Net COM pressing文件，使用下面的code。因为我针对Fx的2.0，我不能使用 Stream.CopyTo 方法。I've just started compressing file in VB.Net, using the following code. Since I'm targ...

我刚刚开始在VB.Net COM pressing文件，使用下面的code。因为我针对Fx的2.0，我不能使用 Stream.CopyTo 方法。

I've just started compressing file in VB.Net, using the following code. Since I'm targeting Fx 2.0, I can't use the Stream.CopyTo method.

我的code，但是，给人非常不好的结果相比，GZIP 正常 COM pression在7-ZIP轮廓。例如，我的code COM pressed一个630MB的前景存档740MB，而7-ZIP使得它490MB。

My code, however, gives extremely poor results compared to the gzip Normal compression profile in 7-zip. For example, my code compressed a 630MB outlook archive to 740MB, and 7-zip makes it 490MB.

下面是code。是否有一个赤裸裸的错误（或多个？）

Here is the code. Is there a blatant mistake (or many?)

Using Input As New IO.FileStream(SourceFile, IO.FileMode.Open, IO.FileAccess.Read, IO.FileShare.Read)
    Using outFile As IO.FileStream = IO.File.Create(DestFile)
        Using Compress As IO.Compression.GZipStream = New IO.Compression.GZipStream(outFile, IO.Compression.CompressionMode.Compress)
            'TODO: Figure out the right buffer size.'
            Dim Buffer(524228) As Byte
            Dim ReadBytes As Integer = 0

            While True
                ReadBytes = Input.Read(Buffer, 0, Buffer.Length)
                If ReadBytes <= 0 Then Exit While
                Compress.Write(Buffer, 0, ReadBytes)
            End While
        End Using
    End Using
End Using

我已经试过多个缓冲区大小，但我得到类似COM pression倍，并具有完全相同的COM pression比。

I've tried with multiple buffer sizes, but I get similar compression times, and exactly the same compression ratio.

推荐答案

修改，或者实际上改写：它看起来像BCL codeRS决定的