我想将输入时间格式化为特定标准:
private String CheckTime(String value)
{
String[] formats = { "HH mm", "HHmm", "HH:mm", "H mm", "Hmm", "H:mm", "H" };
DateTime expexteddate;
if (DateTime.TryParseExact(value, formats, System.Globalization.CultureInfo.InvariantCulture, System.Globalization.DateTimeStyles.None, out expexteddate))
return expexteddate.ToString("HH:mm");
else
throw new Exception(String.Format("Not valid time inserted, enter time like: {0}HHmm", Environment.NewLine));
}
当用户输入时:" 09 00"," 0900"," 09:00"," 9 00", " 9:00"
但是当用户输入它时:"900"
或"9"
系统无法格式化,为什么?
它们是我所采用的默认格式。
string str = CheckTime("09:00"); // works
str = CheckTime("900"); // FormatException at TryParseExact
答案 0 :(得分:1)
嗯匹配" 0900"和H匹配" 09"你必须给2位数。
您可以通过以下方式更改用户输入:
private String CheckTime(String value)
{
// change user input into valid format
if(System.Text.RegularExpressions.Regex.IsMatch(value, "(^\\d$)|(^\\d{3}$)"))
value = "0"+value;
String[] formats = { "HH mm", "HHmm", "HH:mm", "H mm", "Hmm", "H:mm", "H" };
DateTime expexteddate;
if (DateTime.TryParseExact(value, formats, System.Globalization.CultureInfo.InvariantCulture, System.Globalization.DateTimeStyles.None, out expexteddate))
return expexteddate.ToString("HH:mm");
else
throw new Exception(String.Format("Not valid time inserted, enter time like: {0}HHmm", Environment.NewLine));
}
答案 1 :(得分:1)
string time =“900”.PadLeft(4,'0');
如果值为0900,900,9或甚至为0,则上面的行将非常小心;)