一个可以匹配整数、浮点数的正则表达式

//正则表达式

string regStr =  "^[+-]?([0-9]*\.?[0-9]+|[0-9]+\.?[0-9]*)([eE][+-]?[0-9]+)?$";

Description	A regular expression that matches numbers. Integers or decimal numbers with or without the exponential form.
Matches	23 | -17.e23 | +.23e+2
Non-Matches	+.e2 | 23.17.5 | 10e2.0

验证方法如下：

/// <summary>
        /// 验证输入字符串为数字
        /// </summary>
        /// <param name="str">输入字符</param>
        /// <returns>返回一个bool类型的值</returns>
        private static bool IsNumeric(string str)
        {
            System.Text.RegularExpressions.Regex reg1
                = new System.Text.RegularExpressions.Regex(@"^[+-]?([0-9]*\.?[0-9]+|[0-9]+\.?[0-9]*)([eE][+-]?[0-9]+)?$");
            if (str != "")
            {
                return reg1.IsMatch(str);
            }
            else
            {
                return true;
            }
        }