Encoding UTF8 string to ISO-8859-1 String (VB.NET)

Question

I need to convert UTF8 string to ISO-8859-1 string using VB.NET.

Any example?

---

emphasized textI have tried Latin function and not runs. I receive incorrect string.

My case is that I need to send SMS using API.

Now I have this code:

        baseurl = "http://www.myweb.com/api/sendsms.php"
        client = New WebClient
        client.Headers.Add("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; .NET CLR 1.0.3705;)")
        client.Encoding = System.Text.Encoding.GetEncoding("ISO-8859-1")
        client.QueryString.Add("user", user)
        client.QueryString.Add("password", pass)
        client.QueryString.Add("alias", myAlias)
        client.QueryString.Add("dest",  mobile)
        textoSms = Me.mmTexto.Text
        textoSms = System.Web.HttpUtility.UrlEncode(textoSms)
        client.QueryString.Add("message", textoSms)
        data = client.OpenRead(baseurl)
        reader = New StreamReader(data)
        s = reader.ReadToEnd()
        data.Close()
        reader.Close()

But not runs...I receive incorrect messages. For example

if I write: mañana returns maa ana

If I write aigüa returns aiga

Answer 1

How about:

Dim converted as Byte() = Encoding.Convert(utf8, Encoding.UTF8, _
                                           Encoding.GetEncoding(28591))

That assumes that when you say "UTF8 string" you mean "binary data which is the UTF-8 representation of some text". If you mean something else, please specify :)

Note that ISO-8859-1 only represents a tiny proportion of full Unicode. IIRC, you'll end up with "?" for any character from the source data which isn't available in ISO-8859-1.

Answer 2

The encoding ISO-8859-1 is more commonly called Latin-1. You can get this encoding by doing the following

Dim latin1 = Text.Encoding.GetEncoding(&H6FAF)

The full conversion can be done by the following

Public Function ConvertUtf8ToLatin1(Dim bytes As Byte()) As Bytes()
  Dim latin1 = Text.Encoding.GetEncoding(&H6FAF)
  Return Encoding.Convert(Encoding.UTF8, latin1, bytes)
End Function

EDIT

As Jon pointed out, it may be easier for people to remember the decimal number 28591 rather than the hex number &H6FAF.