文件压缩 GZipStream ,解压后文件扩展名丢失,该如何解决

文件压缩 GZipStream ,解压后文件扩展名丢失
我想压缩文件 比如 Text.txt . 我想压缩后得到Text.zip 文件，解压后可以得到Text.txt 文件，可是我怎么一直得到Text 文件没有扩展名.txt .
下面是我的代码：
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

  Dim openFileDialog1 As New OpenFileDialog()
  'openFileDialog1.InitialDirectory = "c:\"
  openFileDialog1.Filter = "All files (*.*)|*.*"
  openFileDialog1.RestoreDirectory = True
  If openFileDialog1.ShowDialog() = Windows.Forms.DialogResult.OK Then

  Dim fileContents As Byte()
  fileContents = My.Computer.FileSystem.ReadAllBytes(openFileDialog1.FileName)
   
  Dim filename As String = openFileDialog1.FileName '& ".zip"
  filename = filename.Substring(0, filename.LastIndexOf("."))
  filename = filename & ".zip"
  If File.Exists(filename) Then File.Delete(filename)
  Dim fs As FileStream = New FileStream(filename, FileMode.CreateNew, FileAccess.Write)

  Dim compressed_Data As Byte()

  compressed_Data = Compress(fileContents)

  If compressed_Data IsNot Nothing Then
  fs.Write(compressed_Data, 0, compressed_Data.Length)
  fs.Close()
  End If
  End If
  End Sub

 Public Function Compress(ByVal data() As Byte) As Byte()

  Try
  Dim ms As New System.IO.MemoryStream()
  Dim zipStream As Stream = Nothing
  zipStream = New GZipStream(ms, CompressionMode.Compress, True)

  zipStream.Write(data, 0, data.Length)
  zipStream.Close()

  ms.Position = 0
  Dim c_data(ms.Length - 1) As Byte
  ms.Read(c_data, 0, ms.Length)
  Return c_data

  Catch ex As Exception

  End Try

  End Function


------解决方案--------------------
GZipStream没用过，我用的unzip没有发现这样问题，建议换为Unzip吧
------解决方案--------------------

C# code

    /// <summary>
    /// 压缩文件
    /// </summary>
    /// <param name="filepath"></param>
    public static void CreateZipFile(string filepath)
    {
        using (FileStream fs = new FileStream(filepath,FileMode.Open))
        {
            byte[] bytes = new byte[fs.Length];
            fs.Read(bytes, 0, bytes.Length);
            
            using (FileStream outfile = File.Create(Path.ChangeExtension(filepath, "zip")))
            {
                using (GZipStream zipStream = new GZipStream(outfile, CompressionMode.Compress))
                {
                    zipStream.Write(bytes, 0, bytes.Length);
                }
            
            }
        }
    
    }

    /// <summary>
    /// 解压缩文件
    /// </summary>
    /// <param name="filepath"></param>
    public static void DeCompressZipFile(string filepath,string extension)
    {
        using (FileStream infile = File.OpenRead(filepath))
        {
            using (DeflateStream deflateStream = new DeflateStream(infile, CompressionMode.Decompress))
            {
                byte[] buffer = new byte[infile.Length + 100];
                int offset = 0;
                int totalCount = 0;
                while (true)
                {
                    int bytesRead = deflateStream.Read(buffer, offset, 100);
                    if (bytesRead == 0)
                    {
                        break;
                    }
                    offset += bytesRead;
                    totalCount += bytesRead;
                }
                using (FileStream outfile = File.Create(Path.ChangeExtension(filepath, extension)))
                {
                    outfile.Write(buffer, 0, buffer.Length);
                }
            }
        }

    }