判斷C#中的字串是否是數字,如果是轉換成int型別

1.通過正則表示式(可以判斷正數和負數)

public int IsNumeric(string str)
        {
            int i;
            if (str != null && System.Text.RegularExpressions.Regex.IsMatch(str, @"^-?\d+$"))
                i = int.Parse(str);
            else
                i = -1;
            return i;
        }

2.通過字元

        ///  
        /// 判斷是否是數字 
        ///  
        ///  
        ///  
        private bool IsNumeric(string number)
        {
            try
            {
                for (int i = 0; i < number.Length; i++)
                {
                    if (number < '0' || number > '9')
                    {
                        return false;
                    }
                }
                return true;
            }
            catch
            {
                return false;
            }
        }

3.通過char.IsNumber方法

　/// 判斷是否是數字 
        ///  
        ///  
        ///  
        private bool IsNumeric(string number)
        {
            try
            {
                for (int i = 0; i < number.Length; i++)
                {
                    if (!char.IsNumber(number, i))
                    {
                        return false;
                    }
                }
                return true;
            }
            catch
            {
                return false;
            }
        }

4.通過try,catch()

        /// 判斷是否是數字 
        ///  
        ///  
        ///  
        private bool IsNumeric(string number)
        {
            try
            {
                int.Parse(number);
                return true;
            }
            catch
            {
                return false;
            }
        }