问题描述
我看过这些 问题 但都涉及在 CellStyle Format 值中不可用的方法.我只想显示小时和分钟部分(16:05)；也不是秒数 (16:05:13).我尝试将秒值强制为零，但仍然得到类似 16:05:00 的结果.如果不使用诸如提供字符串或日期时间(并且仅显示小时/分钟部分)之类的杂项，我是否可以通过任何方式获得格式以执行我想要的操作.
I've seen these questions but both involve methods that aren't available in the CellStyle Format value. I only want to show the hours and minutes portion (16:05); not the seconds as well (16:05:13). I tried forcing the seconds value to zero but still got something like 16:05:00. Short of using a kludge like providing a string or a DateTime (and only showing the hour/minutes part) is there any way I can get the formatting to do what I want.
推荐答案
这是我自己才发现的.不幸的是，解决方案非常复杂.好消息是它有效.
I just discovered this myself. Unfortunately, the solution is pretty involved. The good news is that it works.
首先，您需要一个处理 TimeSpan 值的 ICustomFormatter 实现..NET 框架不包括这种开箱即用的类型；我猜测这是因为 Microsoft 不想处理在格式化 TimeSpan 时所涉及的歧义(例如，hh"是指总小时数还是仅指小时组件?)以及当这些歧义使开发人员感到困惑时会出现的随之而来的支持问题的冲击.
Firstly, you need an ICustomFormatter implementation that deals with TimeSpan values. The .NET framework does not include such a type out-of-the-box; I am guessing this is because Microsoft didn't want to have to deal with the ambiguity involved in formatting a TimeSpan (e.g., does "hh" mean total hours or only the hour component?) and the ensuing onslaught of support issues that would arise when these ambiguities confused developers.
没关系 - 只需实现您自己的.下面是我编写的一个示例类，它基本上使用 与 相同的自定义格式字符串日期时间(无论如何都是适用的)*:
That's OK -- just implement your own. Below is a sample class I wrote that uses basically the same custom format strings as DateTime (those that were applicable, anyway)*:
class TimeSpanFormatter : IFormatProvider, ICustomFormatter
{
private Regex _formatParser;
public TimeSpanFormatter()
{
_formatParser = new Regex("d{1,2}|h{1,2}|m{1,2}|s{1,2}|f{1,7}", RegexOptions.Compiled);
}
#region IFormatProvider Members
public object GetFormat(Type formatType)
{
if (typeof(ICustomFormatter).Equals(formatType))
{
return this;
}
return null;
}
#endregion
#region ICustomFormatter Members
public string Format(string format, object arg, IFormatProvider formatProvider)
{
if (arg is TimeSpan)
{
var timeSpan = (TimeSpan)arg;
return _formatParser.Replace(format, GetMatchEvaluator(timeSpan));
}
else
{
var formattable = arg as IFormattable;
if (formattable != null)
{
return formattable.ToString(format, formatProvider);
}
return arg != null ? arg.ToString() : string.Empty;
}
}
#endregion
private MatchEvaluator GetMatchEvaluator(TimeSpan timeSpan)
{
return m => EvaluateMatch(m, timeSpan);
}
private string EvaluateMatch(Match match, TimeSpan timeSpan)
{
switch (match.Value)
{
case "dd":
return timeSpan.Days.ToString("00");
case "d":
return timeSpan.Days.ToString("0");
case "hh":
return timeSpan.Hours.ToString("00");
case "h":
return timeSpan.Hours.ToString("0");
case "mm":
return timeSpan.Minutes.ToString("00");
case "m":
return timeSpan.Minutes.ToString("0");
case "ss":
return timeSpan.Seconds.ToString("00");
case "s":
return timeSpan.Seconds.ToString("0");
case "fffffff":
return (timeSpan.Milliseconds * 10000).ToString("0000000");
case "ffffff":
return (timeSpan.Milliseconds * 1000).ToString("000000");
case "fffff":
return (timeSpan.Milliseconds * 100).ToString("00000");
case "ffff":
return (timeSpan.Milliseconds * 10).ToString("0000");
case "fff":
return (timeSpan.Milliseconds).ToString("000");
case "ff":
return (timeSpan.Milliseconds / 10).ToString("00");
case "f":
return (timeSpan.Milliseconds / 100).ToString("0");
default:
return match.Value;
}
}
}
我们还没有完成.有了这种类型，您就可以为 DataGridView 中的列分配一个自定义格式化程序，用于显示您的 TimeSpan 值.
We're not finished yet. With this type in place, you are equipped to assign a custom formatter to the column in your DataGridView that you want to use for displaying your TimeSpan values.
假设该列名为时间"；那么你会这样做:
Let's say that column is called "Time"; then you would do this:
DataGridViewColumn timeColumn = dataGridView.Columns["Time"];
timeColumn.DefaultCellStyle.FormatProvider = new TimeSpanFormatter();
timeColumn.DefaultCellStyle.Format = "hh:mm";
所以现在你已经设置好了，对吧?
So now you're set up, right?
好吧，出于某种奇怪的原因，您仍然没有 100% 到达那里.为什么此时自定义格式无法启动，老实说，我无法告诉您.但我们几乎完成了.最后一步是处理 CellFormatting 事件，让我们编写的这个新功能真正生效:
Well, for some odd reason, you're still not 100% of the way there. Why custom formatting can't kick in at this point, I honestly couldn't tell you. But we're almost done. The one final step is to handle the CellFormatting event to get this new functionality we've written to actually take effect:
private void dataGridView_CellFormatting(object sender, DataGridViewCellFormattingEventArgs e)
{
var formatter = e.CellStyle.FormatProvider as ICustomFormatter;
if (formatter != null)
{
e.Value = formatter.Format(e.CellStyle.Format, e.Value, e.CellStyle.FormatProvider);
e.FormattingApplied = true;
}
}
我们终于完成了.设置要根据自定义规则格式化的 DataGridViewColumn 的 DefaultCellStyle.Format 属性现在应该可以按预期工作.
At last, we're finished. Setting the DefaultCellStyle.Format property of the DataGridViewColumn you want formatted according to your custom rules should now work as expected.
这篇关于在 DataGridView 列中格式化 TimeSpan的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！