i want to use regular expression to validate SSN with dashes. This is the format i would like to see: 000-00-0000. This expression does not work for me for some reason.
<asp:RegularExpressionValidator runat="server" Display="Dynamic" ValidationExpression="^(\\d{3}-\\d{2}-\\d{4}|\\d{9})$" ControlToValidate="txtSSN" ForeColor="Red" />
this is how i resolved:
^\d{3}-\d{2}-\d{4}$
There are a few things to note about the RegularExpressionValidator:
It will never be activated by an empty string in the control it is
validating. Only the RequiredFieldValidator catches empty strings You
do not need to specify beginning of string and end of string matching
characters (^ and $)—they are assumed. If you add them, it won't hurt
(or change) anything—it's simply unnecessary.
You could just refer to an example regex on thatpage in MSDN, and see that the value is treated as a verbatim string literal.
So, to only allow SSNs with hyphens, you just need to use:
ValidationExpression="\d{3}-\d{2}-\d{4}"
It is also ECMAScript-compliant and safe to use both at server and client, but you could further limit to
ValidationExpression="[0-9]{3}-[0-9]{2}-[0-9]{4}"
Remember, \d at server-side can also match some non-standard (Arabic, etc) digits.
Related
I'm really bad with regex and was looking at another question almost identical to this but can't get it to work as I need.
I was to use a RegularExpressionValidator that will allow any character up to 255 characters or nothing at all. I tried,
ValidateExpression="^.{255}$"
but it throws an unhanded exception when the textbox that I'm checking is empty.
I've also tried
ValidateExpression="^.{,255}$"
Thank you
Rodney
Did you try ^.{0,255}$? Not sure what exception you are getting though.
EDIT: Also, if struggling with .Net regex, Regex Hero tester is a great help. I know there are other sites, but this one is by far the best, if you ask me.
The proper expression is ^.{0,255}$.
^.{255}$ will only match if there is exactly 255 characters, while ^.{,255}$ will match the literal string "{,255}".
If there are still issues after trying that, can you tell us the exception?
If it throws an HttpRequestValidationException exception, you can use the members of the UnvalidatedRequestValues class.
Mind that "Validation succeeds if the input control is empty" (MSDN). You may add a RequiredFieldValidator field to ensure that the user does not leave a text box blank (if you use the RequiredFieldValidator control inside an UpdatePanel control, make sure that the validator control and the control it is associated with are in the same panel - MSDN):
<asp:textbox id="myTB"
runat="Server">
</asp:textbox>
// ... MAKE SURE YOU DO NOT USE TextMode="Number"!!!
<asp:RequiredFieldValidator
ID="Value1RequiredValidator"
ControlToValidate="myTB"
ErrorMessage="Please enter a number.<br />"
Display="Dynamic"
runat="server"/>
And as for regex, ^.{255}$ means match any character (except newline) exactly 255 times between string start and end. I think it makes sense to allow ^[1-9][0-9]{0,254}$ (for values like '34', '104', etc.).
I want to restrict a text box to accept only two strings i.e true/false using regular expression.
My code is working partially. For lower case, it's working fine but I want it to be case insensitive.
my regular expression looks like this
<asp:RegularExpressionValidator ID="regAssign1" runat="server"
ControlToValidate="tb_Assign" ErrorMessage="Wrong Input!" forecolor="Red"
ValidationExpression="^(true)|(false)$" ValidationGroup="Submit"></asp:RegularExpressionValidator>
I want to get this done using a regular expression validator only. Suggestions using any other options like use JavaScript or use a drop-down list should be avoided.
You should change your regex to:
"^(true|false)$"
Please note that when using that, editor still accept empty string so you need to add a RequiredFieldValidator as well. Also for both of them if you added :
Display="Dynamic"
it would look better.
The simple way is just like this...
^true$|^false$
This version allows whitespace before or after, which you can remove later with Trim.
^\s*true\s*$|^\s*false\s*$
I persistently tried to use ?i: for case insensitivity, it did not work in my RegularExpressionValidator. So here are some possible alternatives that will allow the three most likely case versions "true", "True", and "TRUE".
^true$|^false$|^True$|^False$|^TRUE$|^FALSE$
and allowing whitespace...
^\s*true\s*$|^\s*false\s*$|^\s*True\s*$|^\s*False\s*$|^\s*TRUE\s*$|^\s*FALSE\s*$
Also, as another answer pointed out, you will need a RequiredFieldValidator to disallow an empty TextBox.
Try this regex:
^(?i:true)|(?i:false)$
The i makes comparison case-insensitive for the words following the colon.
Alternatively, try this:
^([T|t][R|r][U|u][E|e])|([F|f][A|a][L|l][S|s][E|e])$
Following expression work well for email validation with asp.net but does not allow whitespace at start and end.
^(([a-zA-Z0-9_\-\.]+)#([a-zA-Z0-9_\-\.]+)\.([a-zA-Z]{2,5}){1,25})+([;.](([a-zA-Z0-9_\-\.]+)#([a-zA-Z0-9_\-\.]+)\.([a-zA-Z]{2,5}){1,25})+)*$
Have any way to allow whitespace?
Here is full asp.net markup, I can not trim before validation.
<asp:TextBox ID="txtEmail" runat="server" MaxLength="100" CssClass="textbg text"></asp:TextBox>
<asp:RegularExpressionValidator ID="EmailValidator" runat="server" ErrorMessage="Email is not vaild."
ForeColor="Red" ControlToValidate="txtEmail" ValidationExpression="^(([a-zA-Z0-9_\-\.]+)#([a-zA-Z0-9_\-\.]+)\.([a-zA-Z]{2,5}){1,25})+([;.](([a-zA-Z0-9_\-\.]+)#([a-zA-Z0-9_\-\.]+)\.([a-zA-Z]{2,5}){1,25})+)*$"
ValidationGroup="register">Email is not vaild.</asp:RegularExpressionValidator>
I would echo the previous points suggesting trimming the input prior to validation. Trimming or ignoring whitespace is a pretty common requirement, so I would be very surprised if your validator couldn't handle it.
I would also point out an email address with that spaces on either end is an invalid email address, so passing it as valid is technically incorrect.
However, if it can't trim it, and you must pass it, then it is trivially easy to modify any regex to allow whitespace at either end.
White space is represented in regex with \s. Zero or more white spaces would be \s*.
Therefore, all you need to do is add \s* to the start and end of the expression, immediately inside the^and$` start and end markers, like so:
/^\s*(.......)\s*$/
(where ...... represents an expression to validate an email address (but probably not the one you've quoted in the question).
Hope that helps.
Email validation using regular expressions are not easy. Since you're using ASP.NET, you could just use the same regular expression MailAddress uses. Presumably most email addresses are not going to be invalid, so the Try...Catch operation shouldn't be too expensive.
MailAddress mailAddress;
try
{
mailAddress = new MailAddress(txtEmail.Text);
}
catch (Exception ex)
{
//Email considered invalid
}
Edit 2 - This one should work with the validator:
(\s?)+\w+(([a-zA-Z0-9_\-\.]+)#([a-zA-Z0-9_\-\.]+)\.([a-zA-Z]{2,5}){1,25})+([;.](([a-zA-Z0-9_\-\.]+)#([a-zA-Z0-9_\-\.]+)\.([a-zA-Z]{2,5}){1,25})+)*(\s?)+
Just be aware, email validation cannot be considered reliable because it's very easy to bypass most of the regular expressions.
Looks like a simple task - get a regex that tests a string for particular length:
^.{1,500}$
But if a string has "\r\n" than the above match always fails!
How should the correct regex look like to accept new line characters as part of the string?
I have a <asp:TextBox TextMode="Multiline"> and use a RegularExpressionValidator to check the length of what user types in.
Thank you,
Andrey
You could use the RegexOptions.Singleline option when validating input. This treats the input as a single line statement, and parses it as such.
Otherwise you could give the following expression a try:
^(.|\s){1,500}$
This should work in multiline inputs.
Can you strip the line breaks before checking the length of the string? That'd be easy to do when validating server-side. (In .net you could use a custom validator for that)
From a UX perspective, though, I'd implement a client-side 'character counter' as well. There's plenty to be found. jQuery has a few options. Then you can implement the custom validator to only run server-side, and then use the character counter as your client-side validation. Much nicer for the user to see how many characters they have left WHILE they are typing.
The inability to set the RegexOptions is screwing you up here. Since this is in a RegularExpressionValidator, you could try setting the options in the regular expression itself.
I think this should work:
(?s)^.{1,500}$
The (?s) part turns on the Singleline option which will allow the dot to match every character including line feeds. For what it's worth, the article here also lists the other RegexOptions and the notation needed to set them as an inline statement.
I have an application in which I want to validate a text box that it will take decimal value.
I would like to use a regular expression validator for this. What would this expression look like?
I wouldn't use a regular expression - create a custom validator that uses Decimal.TryParse under the covers.
Edit: To be fair to the question, here is a regular expression that would do the trick:
^\d*\.?\d+$
just the regex would be
`\d*`
I'd use a CompareValidator - for type decimal
And a Required field Validator - so blank is not allowed
But regular expression is accepable this link gives some examples http://msdn.microsoft.com/en-us/library/ms998267.aspx
I say to keep using the Regular Expression Validator, you'll get the added benefit of client-side validation with it.
Here is a list of regular expressions related to decimals:
http://regexlib.com/DisplayPatterns.aspx?cattabindex=2&categoryId=3
I would use a CompareValidator and use Regular Expression
^\d*[0-9](|.\d*[0-9]|,\d*[0-9])?$
This allow all decimal number, exclude all alphanumeric caracter
e.g.
<asp:RegularExpressionValidator
ID="RegularExpressionValidator1"
runat="server"
ErrorMessage="Only Decimal Value"
ValidationExpression="^\d*[0-9](|.\d*[0-9]|,\d*[0-9])?$">
</asp:RegularExpressionValidator>