Re: Checking for a valid date

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I'm not sure whether IsDate uses Exceptions as the primary mechanism. Does anyone know for sure whether IsDate uses an exception for invalid dates (1) always, (2) sometimes, or (3) never?

If I found out that it did I wouldn't use it; here's an msdn blog that talks about it, the best quote being, "...pretend that the throw statement makes the computer beep 3 times, and sleep for 2 seconds. If you still want to throw under those circumstances, go for it."

http://blogs.msdn.com/ricom/archive/2003/12/19/44697.aspx

The feedback from Jeremy Wilson on this next page seems to indicate that IsDate does not (or at least doesn't use it alone):

http://blogs.crsw.com/mark/archive/2005/04/06/829.aspx

If I found out that IsDate DID rely primarily on an exception for invalid values I would use something similar to that referenced in this next article, the idea being to catch most invalid dates without throwing an exception:

http://searchvb.techtarget.com/vsnetTip/1,293823,sid8_gci960388_tax293037,00.html

Jason

www.pettysconsulting.com


Kerry Moorman wrote: 
Jason,

Doesn't IsDate use this same technique internally?

Kerry Moorman

"Jason Pettys" wrote:


I recommend against this method in most cases; exceptions are resource-intensive and shouldn't really be used for raw user-data validation. It probably wouldn't matter much on a Win Forms app, but I would really back away from this on ASP.NET if you're expecting any volume of traffic.

The IsDate would be a better way to go.

Jason

www.pettysconsulting.com


Armin Zingler wrote:

"romy" <royalizi@xxxxxxxxxxxx> schrieb


What's the easiest way to verify the user had entered a valid date ?



Call Date.Parse in a Try/Catch block. If there's no excecption the date was valid.


Armin 

.

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