检查一个字符串是使用DateTime.TryParse有效日期 [英] Check if a string is a valid date using DateTime.TryParse
问题描述
我使用 DateTime.TryParse（）函数来检查，如果一个特定的字符串是不依赖于任何文化的有效日期时间。
令我惊讶的是，在函数返回真甚至字符串，如1-1，1/1.etc。
I am using DateTime.TryParse() function to check if a particular string is a valid datetime not depending on any cultures.
To my surprise , the function returns true for even strings like "1-1", "1/1" .etc.
我该如何解决这个问题呢？
How can I solve this problem?
更新：
这是否意味着，如果我想检查是否有特定的字符串是有效的日期时间，我需要一个庞大的格式排列？将有不同的组合，我相信。
即使有大量的日期分隔符的（/，。' - '，等等。）根据培养，这将是困难的，我来定义格式要检查的阵列。
基本上，我想检查是否有特定的字符串至少包含一天（1至31或01至31），月（1至12或01至12）和年（yyyy或YY）以任意顺序，与任何日期分隔符，会有怎样的解决方案？
所以，如果该值包括时间任何地方，则它应该返回真太。
我能不能够定义格式的数组。
Does it mean, if I want to check if a particular string is valid datetime, I need a huge array of formats?? There will be different combinations , I believe.
Even there are lots of date separator ( '.' , '/' , '-', etc..) depending on the culture, it will be difficult for me to define an array of format to check against .
Basically, I want to check if a particular string contains AT LEAST day(1 through 31 or 01 through 31),month(1 through 12 or 01 through 12) and year(yyyy or yy) in any order, with any date separator , what will be the solution?
So, if the value includes any parts of time, it should return true too.
I could NOT be able to define a array of format.
推荐答案
如果您希望您的日期，以符合特定的格式或格式，然后使用的 DateTime.TryParseExact 否则就是 DateTime.TryParse
If you want your dates to conform a particular format or formats then use DateTime.TryParseExact otherwise that is the default behaviour of DateTime.TryParse
该方法尝试为忽略不可识别的数据，如果可能的话，和 填写缺少的月，日和年信息与当前 日期。如果s只包含日期而没有时间，则此方法假设 时间是午夜12点。如果s包括日期组分与 两位数的年份，它被转换为一年，在当前文化的 基于所述Calendar.TwoDigitYearMax的值当前日历 属性。以s任何领先的，内在的，或尾随空白字符 被忽略。
This method tries to ignore unrecognized data, if possible, and fills in missing month, day, and year information with the current date. If s contains only a date and no time, this method assumes the time is 12:00 midnight. If s includes a date component with a two-digit year, it is converted to a year in the current culture's current calendar based on the value of the Calendar.TwoDigitYearMax property. Any leading, inner, or trailing white space character in s is ignored.
如果您想确认对多种格式再看看 DateTime.TryParseExact方法（字符串，字符串[] ，IFormatProvider的，DateTimeStyles，日期时间）超载。从同一链路示例：
If you want to confirm against multiple formats then look at DateTime.TryParseExact Method (String, String[], IFormatProvider, DateTimeStyles, DateTime) overload. Example from the same link:
string[] formats= {"M/d/yyyy h:mm:ss tt", "M/d/yyyy h:mm tt",
"MM/dd/yyyy hh:mm:ss", "M/d/yyyy h:mm:ss",
"M/d/yyyy hh:mm tt", "M/d/yyyy hh tt",
"M/d/yyyy h:mm", "M/d/yyyy h:mm",
"MM/dd/yyyy hh:mm", "M/dd/yyyy hh:mm"};
string[] dateStrings = {"5/1/2009 6:32 PM", "05/01/2009 6:32:05 PM",
"5/1/2009 6:32:00", "05/01/2009 06:32",
"05/01/2009 06:32:00 PM", "05/01/2009 06:32:00"};
DateTime dateValue;
foreach (string dateString in dateStrings)
{
if (DateTime.TryParseExact(dateString, formats,
new CultureInfo("en-US"),
DateTimeStyles.None,
out dateValue))
Console.WriteLine("Converted '{0}' to {1}.", dateString, dateValue);
else
Console.WriteLine("Unable to convert '{0}' to a date.", dateString);
}
// The example displays the following output:
// Converted '5/1/2009 6:32 PM' to 5/1/2009 6:32:00 PM.
// Converted '05/01/2009 6:32:05 PM' to 5/1/2009 6:32:05 PM.
// Converted '5/1/2009 6:32:00' to 5/1/2009 6:32:00 AM.
// Converted '05/01/2009 06:32' to 5/1/2009 6:32:00 AM.
// Converted '05/01/2009 06:32:00 PM' to 5/1/2009 6:32:00 PM.
// Converted '05/01/2009 06:32:00' to 5/1/2009 6:32:00 AM.
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