VB.net读取不同编码文本 解决乱码问题

Public Function ReadAsString(ByVal buff() As Byte) As String
Dim stream As Stream = New MemoryStream(buff)
Dim position As Int64 = 0
Try
stream.Position = position
Dim reader As New StreamReader(stream, New UTF8Encoding(False, True), True)
Return reader.ReadToEnd
Catch exception As DecoderFallbackException
stream.Position = position
Dim reader2 As New StreamReader(stream, Encoding.Default) '.GetEncoding(&H4E4))
'Debug.Print(reader2.CurrentEncoding.ToString)
Return reader2.ReadToEnd
Catch ex As Exception
Debug.Print(ex.Message & vbCrLf & ex.StackTrace)
End Try
Return ""
End Function

c#和asp.net的版本参见下面的链接：
http://stackoverflow.com/questions/90838/how-can-i-detect-the-encoding-codepage-of-a-text-file/5830273#5830273