I have a source XML that uses a dot (\".\") as a decimal separator and I am parsing this on a system that uses a comma (\",\") as a decimal separator.
As a result,
XML standard is explicit about the formatting of dates and numbers etc. This helps to ensure that the XML is platform independent and interoperable. Take a look at using XmlConvert for xml data.
double value = XmlConvert.ToDouble(stringValue);