验证 .NET 时间格式的正则表达式

Question

Background

I need to validate user input in some fields, where these are defining how to show time in some views.

Requirements

Time format must be expressed in Microsoft .NET way (check this MSDN Library article if you want to learn more about framework's date and time formatting: http://msdn.microsoft.com/en-us/library/8kb3ddd4.aspx )

Keep in mind I'm looking to validate the format instead of an actual time string.

For example, user may input:

• HH:mm
• hh:mm
• ss
• hh:ss
• mm:ss
• ... and so on.

In fact, it should validate from the shortest to longest time format available.

Another point is I need to do it in client-side using JavaScript . In other words, any given regular expression by you should work in browsers JavaScript regular expressions' engine.

I'll appreciate any self-taylored one, any link or pasted expression!

Thank you in advance.

NOTE (Update)

I can't use ASP.NET validation engine, or any other. Because of project's requirements, I need to avoid that.

Answer 1

As far as I understand, there is no much options - sort of 20, as maximum. Why not just enumerate them all in one big regex without much special symbols? Like

'hh:mm|hh:mm:ss|yyyy-MM-dd hh:mm|<etc>'

you could than make it case sensitive to differentiate between M for month and m for minute, and for hours make it [hH] , then make it [:-/] there where you allow for different separators, and lots of other similar things. But the main idea is to simply enumerate all options separated by | with just little amount of regex syntax between | and | .

Answer 2

What is your definition of a "valid" format string? Only once you know that can it be possible to validate a format string.

"K" is also a valid format string

"zz" is also a valid format string

"e" is also a valid format (it would fall into the "The character is copied to the result string unchanged." case)

I'm not even sure what formats would actually cause .NET.ToString() to throw an exception (if that's what you are trying to avoid).