答案:使用decimal类型代替float或者double
举例说明
decimal amount = Convert.ToDecimal(record.Amount);
decimal sum = 1.20m + amount * 100.0m;
参考来自
https://stackoverflow.com/questions/3204989/multiplying-a-double-value-by-100-0-introduces-rounding-errors
https://docs.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/decimal