date regular expressions in .net

@"(([0-9]{1,31})[/|-|(\s)]([0-9]{1,12})[/|-|(\s)](\d{4}|\d{2}))"
//DD/MM/YY(YY)
@"(([0-9]{1,12})[/|-|(\s)]([0-9]{1,31})[/|-|(\s)](\d{4}|\d{2}))"
//MM/DD/YY(YY)
@"((\d{4}|\d{2})[/|-|(\s)]([0-9]{1,31})[/|-|(\s)]([0-9]{1,12}))"
//YY(YY)/DD/MM
@"((\d{4}|\d{2})[/|-|(\s)]([0-9]{1,12})[/|-|(\s)]([0-9]{1,31}))"
//YY(YY)/MM/DD
@"(([0-9]{1,12})[/|-|(\s)](\d{4}|\d{2})[/|-|(\s)]([0-9]{1,31}))"
//MM/YY(YY)/DD
@"(([0-9]{1,31})[/|-|(\s)](\d{4}|\d{2})[/|-|(\s)]([0-9]{1,12}))"
//DD/YY(YY)/MM
@"^(([0-9]{1,2})(\s)?(Jan(uary)?|Feb(ruary)?|(Ma(r(ch)?|y))|Apr(il)?|Ju(n(e)?|l(y)?)|Aug|Oct(ober)?|(Sep(t)?|Nov|Dec)(ember)?)(\s)?(\d{2}|\d{4}))$"
//DD()MMM()YYYY