Not all encodings are included in the Xamarin.iOS class library by default.
To reduce the size of the application, Xamarin.iOS doesn't include any specific encoding, and you have to instruct mtouch to include the assemblies containing the support for the encoding you need.
This is done by selecting the extra encodings from the iOS Build/Advanced pane in Xamarin Studio or Visual Studio:
You can select one of these:
- cjk: for Chineese, Japaneese and Korean
- mideast: Arabic, Hebrew, Turkish and Latin5.
- other: Cyrillic, Baltic, Vietnamese, Ukranian and Thai
- rare: EBCDIC encodings and other rare code pages
- west: Latin languages, Easter and Western European