c# - 将相对日期时间字符串转换为 DateTime 对象

Question

我有相对的 datetime 字符串:

• “5 分钟前”
• “10 小时前”
• “3 天前”等

如何将其转换为精确的 datetime，与 this question 正好相反

Answer 1

这段代码应该可以工作:

        string input = "10 days ago";

        DateTime result = DateTime.MinValue;
        int minutesMultiplier = 0;

        if (input.Contains("minute"))
            minutesMultiplier = 1;
        else
            if (input.Contains("hour"))
                minutesMultiplier = 60;
            else
                if (input.Contains("day"))
                    minutesMultiplier = 1440;
                else
                    throw new Exception("Couldn't parse time format");

        string numberStr = input.Split(' ')[0];
        int number;
        if (int.TryParse(numberStr, out number))
            result = DateTime.Now.AddMinutes(-number * minutesMultiplier);

它解析间隔名称(例如分钟、小时、天)并将它们相乘得到分钟数，因为稍后它使用 DateTime.Now.AddMinutes 方法，同样的事情可以使用 TimeSpan 并调用 DateTime.Now.Add 来完成。

这是处理包含多个间隔名称的字符串大小写的另一个示例，例如“10 小时 15 分钟前”:

        // If there are mixed interval types in an input string
        string input = "10 days and 10 hours ago";

        // Parse out the intervals and numbers
        var matches = Regex.Matches(input, 
                       @"(?<number>\d+)\s(?<interval>(day)|(minute)|(hour))");

        // Convert them to dictionary
        var dic = matches
            .Cast<Match>()
            .ToDictionary(
                key => key.Groups["interval"].Value, 
                o => int.Parse(o.Groups["number"].Value));

        // Calculate the total number of minutes for each interval
        DateTime result = DateTime.MinValue;
        int totalMinutes = 0;

        foreach (var keyValue in dic)
        {
             if (keyValue.Key.Contains("minute"))
                 totalMinutes += keyValue.Value;
            else
                 if (keyValue.Key.Contains("hour"))
                    totalMinutes += keyValue.Value * 60;
                else
                     if (keyValue.Key.Contains("day"))
                        totalMinutes += keyValue.Value * 1440;
                    else
                        throw new Exception("Unparsable time format");
        }

        result = DateTime.Now.AddMinutes(-totalMinutes);