How about:
...
string input = ...;
Match match = Regex.Match(input, @"\w+\s*=\s*(\d+(?:\.\d+)?\s*[A-Z]+)");
string size = match.Success ? match.Groups[1].Value : string.Empty;
...
Depends very much on the input string if the
@
and
{
are relevant to properly match the text.
Note: If you need to be culture aware, the whole regex becomes far more difficult: decimal separator and thousand separator may be rather "weird" in versious cultures (e.g. some scandinavian language, the thousand separator is some kind of space...). In that case, you need to be a bit more fuzzy, e.g.
@"\w+\s*=\s*(.*?\s*[A-Z][A-Z])"
.
Cheers
Andi