使用 Discord 机器人进行 C# 时间减法

Question

我正在制作一个有趣的 Discord 机器人，它可以在时钟上找到下一个 4:20，无论是上午还是下午，并告诉你距离 4:20 还有多长时间。我的代码在 4:20 前一个小时之前运行良好，然后它会向前跳并告诉下一个 4:20 需要多长时间，而不是显示“0 小时 59 分钟”。我在想我如何格式化时间输出可能存在问题，但我对 C# 很陌生，也不知道如何解决它。我已经包含了我的代码以及当前输出的屏幕截图。在屏幕截图中，机器人也有一分钟的时间，但从那时起我就想出了如何解决这个问题。我知道代码不是最高效或最干净的，但我还是对编程很陌生。

//Finds next 4:20 on the clock
[Command("420")]
public async Task WeedMinute()
{
    DateTime currentTime = DateTime.Now; //Current time
    DateTime weedMinuteMorning = Convert.ToDateTime("4:21:00"); //4:20am
    DateTime weedMinuteEvening = Convert.ToDateTime("16:21:00"); //4:20pm

    string weedMinutePM = "16:21:00"; //These variables are used in subtraction
    string weedMinuteAM = "4:21:00";


    if (currentTime <= weedMinuteEvening)
    {
        //chooseMorningEvening is the output time string
        DateTime chooseMorningEvening = (DateTime.Parse(weedMinutePM).Subtract(currentTime.TimeOfDay));

        await Context.Channel.SendMessageAsync("The next weed minute will happen in " + chooseMorningEvening.ToString(@"hh") + " hours " + chooseMorningEvening.ToString(@"mm") + " minutes.");
    }
    else if (currentTime >= weedMinuteMorning)
    {
        //chooseMorningEvening is the output time string
        DateTime chooseMorningEvening = (DateTime.Parse(weedMinuteAM).Subtract(currentTime.TimeOfDay));

        await Context.Channel.SendMessageAsync("The next weed minute will happen in " + chooseMorningEvening.ToString(@"hh") + " hours " + chooseMorningEvening.ToString(@"mm") + " minutes.");
    }
}

Answer 1

你的代码的问题是它没有处理所有可能发生的情况（有三种）：

• 时间在 00:00:00 和 04:20:00 之间 => 计算时间到 04:20:00
• 时间在 04:20:00 到 16:20:00 => 计算时间到 16:20:00
• 时间在 16:20:00 之后 => 计算时间到第二天 04:20:00。

如果您观察到下一次标记的时间应该始终在 0 到 12 小时之间，您可以稍微简化一下。所以，如果你只花时间到 16:20，如果超过 12 小时，那么你必须在 04:20 之前起床，你可以减去 12 小时。如果时间小于 0（即负数），那么您必须晚于 16:20，因此您只需添加 12 小时。在代码中是这样的：

    public static TimeSpan CalculateTimeToWeed(DateTime from)
    {
        DateTime weedTime = Convert.ToDateTime("16:20:00");
        TimeSpan twelveHours = TimeSpan.FromHours(12.0);

        TimeSpan timeToWeed = weedTime - from;
        double totalHours = timeToWeed.TotalHours;
        if (totalHours > 12.0)
        {
            timeToWeed -= twelveHours;
        }
        else if (totalHours < 0.0)
        {
            timeToWeed += twelveHours;
        }
        return timeToWeed;
    }

您可以将其集成到您的 Discord 机器人中，如下所示：

    [Command("420")]
    public async Task WeedMinute()
    {
        DateTime currentTime = DateTime.Now; 
        TimeSpan timeToWeed = CalculateTimeToWeed(currentTime);
        string message = "The next weed minute will happen in " + timeToWeed.ToString("hh' hours 'mm'  minutes.'");
        await Context.Channel.SendMessageAsync(message);
    }

您可以减少其中的行数，但是拥有这些临时变量会使事情更容易调试。您可以在使用调试器单步执行时检查currentTime 是否符合您的预期，timeToWeed 是否合理等等。

将代码分成两个函数也有很多优点：

• 您可以独立于机器人测试时间计算
• 代码更清晰，没有把通信代码和计算代码混为一谈。

希望这会有所帮助。

Answer 2

您的时间输出格式似乎没问题，只是为了获得更好的格式，请参阅Custom TimeSpan format strings.

您的代码存在三个问题：

1. 如果条件

if (currentTime <= weedMinuteEvening)
{
    //this condition is true from 00:00:00 to 16:21:01 so for dates less than 4:21:00
    //you get incorrect output, and next condition execute just for dates greater than 16:21:00.
    ...
}
else if (currentTime >= weedMinuteMorning)
{
   //This code execute only for dates greater than 16:21:00.
    ...
}

1. 按照 Adam 的建议，您必须从 currentTime 中删除 .TimeOfDay，但这还不够。

2. 您必须处理大于 16:21:00 的日期

所以我希望这段代码对你有用：

[Command("420")]
public async Task WeedMinute()
{
    DateTime currentTime = DateTime.Now; //Current time
    DateTime weedMinuteMorning = Convert.ToDateTime("4:21:00"); //4:20am
    DateTime weedMinuteEvening = Convert.ToDateTime("16:21:00"); //4:20pm

    //I removed These variables, Don't need to parse same DateTime again. change it as you wish
    //string weedMinutePM = "16:21:00";
    //string weedMinuteAM = "4:21:00";

    if (currentTime <= weedMinuteMorning)
    {
        TimeSpan timeSpan = weedMinuteMorning.Subtract(currentTime);

        await Context.Channel.SendMessageAsync("The next weed minute will happen in " + timeSpan.ToString("hh' hours 'mm'  minutes.'"));
    }
    else if (currentTime <= weedMinuteEvening)
    {
        TimeSpan timeSpan = weedMinuteEvening.Subtract(currentTime);

        await Context.Channel.SendMessageAsync("The next weed minute will happen in " + timeSpan.ToString("hh' hours 'mm'  minutes.'"));
    }
    else
    {
        //To handle dates greater than 16:21:00, we must calculate hours
        //remaining until 4:20 next day.
        weedMinuteMorning = weedMinuteMorning.AddDays(1);
        TimeSpan timeSpan = weedMinuteMorning.Subtract(currentTime);

        await Context.Channel.SendMessageAsync("The next weed minute will happen in " + timeSpan.ToString("hh' hours 'mm'  minutes.'"));

    }
}

Answer 3

这里有一个 DateTime.Compare 函数可以用来修复如下错误

            //DateTime currentTime = DateTime.Now; //Current time
            DateTime currentTime = Convert.ToDateTime("3:22:00");  // An example time for 0 hours and 59 mins
            DateTime weedMinuteMorning = Convert.ToDateTime("4:21:00"); //4:20am
            DateTime weedMinuteEvening = Convert.ToDateTime("16:21:00"); //4:20pm

            string weedMinutePM = "16:21:00"; //These variables are used in subtraction
            string weedMinuteAM = "4:21:00";

            if(currentTime.CompareTo(weedMinuteMorning) < 1)  //less than or same as Morning 4:20 am
            {
                var chooseMorningEvening = weedMinuteMorning - currentTime;
                string m = "The next weed minute will happen in " + chooseMorningEvening.Hours + " hours " + chooseMorningEvening.Minutes + " minutes.";
            }
            else
            {
                var chooseMorningEvening = weedMinuteEvening - currentTime;
                string m = "The next weed minute will happen in " + chooseMorningEvening.Hours + " hours " + chooseMorningEvening.Minutes + " minutes.";
            }