Binance.TradeRobot.API/Binance.TradeRobot.Common/Extensions/MathExtension.cs

using System;

namespace Binance.TradeRobot.Common.Extensions
{
    public static class MathExtension
    {
        /// <summary>
        /// 四舍五入保留小数
        /// </summary>
        /// <param name="d"></param>
        /// <param name="length">保留的位数</param>
        /// <returns></returns>
        public static decimal Round(this decimal d, int length)
        {
            return Math.Round(d, length, MidpointRounding.AwayFromZero);
        }

        /// <summary>
        /// string转换decimal
        /// </summary>
        /// <param name="s"></param>
        /// <param name="length"></param>
        /// <returns></returns>
        public static decimal ToDecimal(this string s, int? length = null)
        {
            if (!decimal.TryParse(s, out decimal d))
                return 0M;
            if (length != null)
                return d.Round(length.Value);
            return d;
        }

        /// <summary>
        /// 截取小数位数,不进行四舍五入
        /// </summary>
        /// <param name="d"></param>
        /// <param name="length">截取的位数</param>
        /// <returns></returns>
        public static decimal CutDecimal(this decimal d, int length)
        {
            var dStr = d.ToString();
            var dotIndex = dStr.IndexOf(".");
            var cutLength = dotIndex + 1 + length;
            if (dotIndex == -1 || dStr.Length <= cutLength)
                dStr = string.Format($"{{0:F{length}}}", d);
            else
                dStr = dStr.Substring(0, cutLength);
            return decimal.Parse(dStr);
        }
    }
}