Vietnamese characters in contents

Aug 2, 2013 at 12:14 AM
I've been using DotNetZip for a while but just ran into a problem. I have some text (not the filename but the actual text contents) which includes non-Latin characters (specifically Vietnamese). When I use DotNetZip to zip up this content, every time I unzip it, the text is garbled (changed in a bad way).
    Dim strOriginal As String = "Đinh Quỳnh Ngô Nguyễn Phạm Tuấn Vũ Phương Ngọc Châu Trần Thị Ngọc Hồng Hiền Tô"
    Using zip As New Ionic.Zip.ZipFile()
        zip.AlternateEncoding = System.Text.Encoding.Unicode
        zip.AlternateEncodingUsage = Ionic.Zip.ZipOption.Always
        zip.AddEntry("data", strOriginal)
        zip.Save("test.zip")
    End Using

    Dim strContents As String
    Using zip As New Ionic.Zip.ZipFile("test.zip")
        Using ms As New System.IO.MemoryStream()
            zip.Entries(0).Extract(ms)
            ms.Position = 0
            Using sr As New System.IO.StreamReader(ms)
                strContents = sr.ReadToEnd
                sr.Close()
            End Using
            ms.Close()
        End Using
    End Using
    If strOriginal = strContents Then
        MsgBox("Happy")
    Else
        MsgBox("Sad")
    End If
I've tried the following Encoding options: UTF7, UTF8, Unicode, UTF32, and BigEndianUnicode. All produce bad results.

Is this a bug or is my implementation off somehow?

In case it matters, I'm using VB.Net 2010, Win7 x64, .Net 3.5, and DotNetZip 1.9.1.8.
Aug 6, 2013 at 4:58 AM
Added as a work item.