正则表达式

 #region 验证手机号码
        /// <summary>
        /// 验证手机号码
        /// </summary>
        /// <param name="strTelephone">手机号码</param>
        /// <returns></returns>
        public static bool IsTelephone(string strTelephone)
        {
            return Regex.IsMatch(strTelephone, "^1\\d{10}$");
        }
        #endregion

        #region 验证Base64编码格式
        /// <summary>
        /// 验证Base64编码格式
        /// </summary>
        /// <param name="eStr">Base64编码</param>
        /// <returns></returns>
        public static bool IsBase64(string eStr)
        {
            if ((eStr.Length % 4) != 0)
            {
                return false;
            }
            if (!Regex.IsMatch(eStr, "^[A-Z0-9/+=]*$", RegexOptions.IgnoreCase))
            {
                return false;
            }
            return true;
        }
        #endregion

#region 将字符串转换为Int32类型
        /// <summary>
        /// 将字符串转换为Int32类型
        /// </summary>
        /// <param name="expression">要转换的字符串</param>
        /// <param name="defValue">缺省值</param>
        /// <returns>转换后的int类型结果</returns>
        public static int ToInt(string expression, int defValue)
        {
            if (string.IsNullOrEmpty(expression) || expression.Trim().Length >= 11 || !Regex.IsMatch(expression.Trim(), @"^([-]|[0-9])[0-9]*(\.\w*)?$"))
                return defValue;

            int rv;
            if (Int32.TryParse(expression, out rv))
                return rv;

            return Convert.ToInt32(ToFloat(expression, defValue));
        }
        #endregion

#region string型转换为decimal型
        /// <summary>
        /// string型转换为decimal型
        /// </summary>
        /// <param name="strValue">要转换的字符串</param>
        /// <param name="defValue">缺省值</param>
        /// <returns>转换后的decimal类型结果</returns>
        public static decimal ToDecimal(string expression, decimal defValue)
        {
            if ((expression == null) || (expression.Length > 10))
                return defValue;

            decimal intValue = defValue;
            if (expression != null)
            {
                bool IsDecimal = Regex.IsMatch(expression, @"^([-]|[0-9])[0-9]*(\.\w*)?$");
                if (IsDecimal)
                    decimal.TryParse(expression, out intValue);
            }
            return intValue;
        }
        #endregion

#region string型转换为float型
        /// <summary>
        /// string型转换为float型
        /// </summary>
        /// <param name="strValue">要转换的字符串</param>
        /// <param name="defValue">缺省值</param>
        /// <returns>转换后的int类型结果</returns>
        public static float ToFloat(string expression, float defValue)
        {
            if ((expression == null) || (expression.Length > 10))
                return defValue;

            float intValue = defValue;
            if (expression != null)
            {
                bool IsFloat = Regex.IsMatch(expression, @"^([-]|[0-9])[0-9]*(\.\w*)?$");
                if (IsFloat)
                    float.TryParse(expression, out intValue);
            }
            return intValue;
        }
        #endregion

#region string型转换为double型
        /// <summary>
        /// string型转换为double型
        /// </summary>
        /// <param name="strValue">要转换的字符串</param>
        /// <param name="defValue">缺省值</param>
        /// <returns>转换后的double类型结果</returns>
        public static double ToDouble(string expression, double defValue)
        {
            if (expression == null)
                return defValue;

            double intValue = defValue;
            if (expression != null)
            {
                bool IsFloat = Regex.IsMatch(expression, @"^([-]|[0-9])[0-9]*(\.\w*)?$");
                if (IsFloat)
                    double.TryParse(expression, out intValue);
            }
            return intValue;
        }
        #endregion