Any on knows why, when I generate a HTML email the result appear with these little strange “black question marks” ? They are not in the source HTML code.
Look the image:
This should answer your question:
http://blog.xojo.com/2013/08/20/why_are_there_diamonds_in_my_user_interface/
Great! Could you suggest me how can I convert the encoding to UTF-8?
Like the article says:
Assign an encoding to your string with http://documentation.xojo.com/index.php/DefineEncoding or pass a TextEncoding if you are using a feature like BinaryStream that supports the encoding. Using Text instead of string may also be helpful, although text is a bit slower. But it always contains a defined encoding.