public static TV TryParseToNull <TV>(this string obj, TryWithOutFunc <string, TV> func) where TV : class
{
TV v; return(obj == null ? null : func(obj, out v) ? v : null);
}
public static TV?TryParseToNullable <TV>(this string obj, TryWithOutFunc <string, TV> func) where TV : struct
{
TV v; return(func(obj, out v) ? v : (TV?)null);
}