General Regular Expression Class

This is a regular expression class for handling most of the validation. I have created this for my project use. All general validations like check for emails, empty, isnumeric have been included in this Class.

A Small Snippet from the Class is here for your reference...

public static bool IsNumber(string str)
        {
            Regex objNotNumberPattern = new Regex("[^0-9.-]");
            Regex objTwoDotPattern = new Regex("[0-9]*[.][0-9]*[.][0-9]*");
            Regex objTwoMinusPattern = new Regex("[0-9]*[-][0-9]*[-][0-9]*");
            String strValidRealPattern = "^([-]|[.]|[-.]|[0-9])[0-9]*[.]*[0-9]+$";
            String strValidIntegerPattern = "^([-]|[0-9])[0-9]*$";
            Regex objNumberPattern = new Regex("(" + strValidRealPattern + ")|(" + strValidIntegerPattern + ")");

            return !objNotNumberPattern.IsMatch(str) &&
                   !objTwoDotPattern.IsMatch(str) &&
                   !objTwoMinusPattern.IsMatch(str) &&
                   objNumberPattern.IsMatch(str);
        }


        public static bool IsValidEmail(string email)
        {
            //regular expression pattern for valid email
            //addresses, allows for the following domains:
            //com,edu,info,gov,int,mil,net,org,biz,name,museum,coop,aero,pro,tv
            string pattern = @"^[-a-zA-Z0-9][-.a-zA-Z0-9]*@[-.a-zA-Z0-9]+(\.[-.a-zA-Z0-9]+)*\.
    (com|edu|info|gov|int|mil|net|org|biz|name|museum|coop|aero|pro|tv|[a-zA-Z]{2})$";
            //Regular expression object
            Regex check = new Regex(pattern, RegexOptions.IgnorePatternWhitespace);
            //boolean variable to return to calling method
            bool valid = false;

            //make sure an email address was provided
            if (string.IsNullOrEmpty(email))
            {
                valid = false;
            }
            else
            {
                //use IsMatch to validate the address
                valid = check.IsMatch(email);
            }
            //return the value to the calling method
            return valid;
        }