ASP.Net Regular Expression Validation of String Length - asp.net

Question

I want to validate if the string entered by user into a text box is at least 3 characters long. I was using following regex:
\w{3,40}
But it fails if user enters say:
my valid string
I want something that will validate the total string length including spaces between the words but not at end or beginning of the string.
So following are valid:
"a bc"
"a b c"
"abc"
"a b c"
but following are not:
"a b "
" a "
" bc"
NOTE:- It is to be done on client side as any changes to server side code will require restarting site which I don't want to do.

Answer 1

Call Trim method in the input and try to use this as your regex pattern:
[\w\s]{3,40}
\s will matches all whitespaces characters.
I test it in here
More: Regular Expression Basic Syntax Reference

Answer 2

I'm guessing you are just having fun with regular expressions but the following check should work:
if ( s.Trim().Length >= 3 )
{
// do awesome stuff here that you would never do with some other crazy string
}

Answer 3

I am still waiting for the working regex. I have tried following, but it fails if there is a space at end of the string:
^[\S|\S\s]{2,40}\S$
Meanwhile I am using following approach to passon custom validation function:
function pageLoad() {
var val = document.all ? document.all["<%=control.ClientID%>"] :
document.getElementById("<%=control.ClientID%>");
if (val) {
val.evaluationfunction = function () {
try {
var v = ValidatorGetValue(val.controltovalidate);
v = ValidatorTrim(v);
return v.length >= 3;
} catch (err) {
return true;
}
};
}
}
Note that most of it is picked from Microsoft ASP.Net Javascript Validation library itself.

Answer 4

Try this and let me know if it works...
Note: Not tested
[A-Za-z]{3}([A-Za-z]+ ?)*