[學習] 在C#實現VB函式【IsNumeric】

【CODE】

        static bool IsNumeric(object Expression)
        {
            // Variable to collect the Return value of the TryParse method.
            bool isNum;
            // Define variable to collect out parameter of the TryParse method. If the conversion fails, the out parameter is zero.
            double retNum;
            // The TryParse method converts a string in a specified style and culture-specific format to its double-precision floating point number equivalent.
            // The TryParse method does not generate an exception if the conversion fails. If the conversion passes, True is returned. If it does not, False is returned.
            isNum = Double.TryParse(Convert.ToString(Expression), System.Globalization.NumberStyles.Any, System.Globalization.NumberFormatInfo.InvariantInfo, out retNum);
            return isNum;
        }

【CODE】

        public static bool IsNum(String str)
        {
            for (int i = 0; i < str.Length; i++)
            {
                if (str[i] < '0' || str[i] > '9')
                    return false;
            }
            return true;
        }

參考：
判断一个字符串是否全是数字的多种方法及其性能比较（C#实现）
[C#]IsNumeric 判斷是否為數值
[C#]數值驗證 IsNumeric
C# Equivalent of VB's IsNumeric()
C# IsNumeric
C#的判斷是否為數字，難道只能用Try、Catch嗎?..沒有VB.NET的IsNumeric可用嗎