Visual Basic base64解码无法正确解码

Question

    Dim base64encoded As String = separatedText
    Dim base64decoded As String
    Dim data() As Byte
    data = System.Convert.FromBase64String(base64encoded)
    base64decoded = System.Text.Encoding.Unicode.GetString(data)
    Console.OutputEncoding = System.Text.Encoding.UTF8
    My.Computer.FileSystem.WriteAllText("C:\test.txt", base64decoded, True)

所选符号是俄语符号 必须解码并保存这样

但是在外面有这样的