isNAN function in C# 1

[jwpward]

Hi

I'm looking for a bit of code that will force a value entered into a text box to be a number.

I know that in javascipt, for example, you could use something like:

if (isNaN(txtMonth.value)== true) {
		alert("Date of birth cannot contain letters or symbols");
	return;
}

..but I'm not sure of the best way to reproduce this in C#

Thanks alot in advance

 

[chmohan]

check for keydown or keypress events and block any character which is not a number (or backspace,enter etc)

 

[chmohan]

this may give some more options

http://www.experts-exchange.com/Programming/Programming_Languages/Dot_Net/Q_20694244.html

 

[tgreer]

Regular expression... cast to an integer in a try block... those are both C# techniques (meaning, server-side). If you wish to do it client-side, then just use JavaScript isNaN.

Thomas D. Greer

http://www.tgreer.com

 

[chiph]

NaN's are only applicable to floating-point types (Double and Single). The .net framework has these values (defined by the IEEE), and you check for them like this:

if (value == Double.NaN)
   // throw exception, etc.

Chip H.


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[JurkMonkey]

Chip - You da man!

 

[jwpward]

Hi

Thanks so much for all your replies. Very helpful indeed.

Chip H - thanks for the code. That's done the job.

Cheers