?
Solved

.NET Validation

Posted on 2006-07-03
8
Medium Priority
?
241 Views
Last Modified: 2010-05-18
I havve a form with a Regular Expression Validator.  I am trying to get it to not allow any speical characters only letters and numbers and I also want it to not allow it to start with a number.  What expression would I use and could someone also explain what the expression is doing?
0
Comment
Question by:johnywhite
8 Comments
 
LVL 96

Expert Comment

by:Bob Learned
ID: 17033751
Regular expression:

^[A-Za-z0-9]+$

Starting at the beginning of the string, replicate any number of upper-case letters, lower-case letters and numbers until the end of the string is reached.

Bob
0
 
LVL 18

Accepted Solution

by:
Ravi Singh earned 2000 total points
ID: 17033776
Try:

^[A-Za-z]+([A-Za-z]|[0-9])*

The above will match a string that begins with one or more letters, then a sequence of zero or more letters or digits ( | is the alternation symbol)

0
 

Author Comment

by:johnywhite
ID: 17033790
That's what I was looking for thanks.
0
Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 64

Expert Comment

by:Fernando Soto
ID: 17033792
Regular Expression to allow alpha a first character and alpha numeric after.

     ^[a-zA-Z][a-zA-Z0-9]*$

Where:
    ^ Marks the begining of the string
    [a-zA-Z] Which only allows one alpha to start the string
    [a-zA-Z0-9] Which only allows one alpha numeric starting at the second character
    * Quantifier Which states allow zero or more of the previous character
    $ Marks the end of the string

Fernando
0
 
LVL 18

Expert Comment

by:Ravi Singh
ID: 17033803
add the $ (end of string) symbol if you dont want leading spaces or spaces within the entire string...

^[A-Za-z]+([A-Za-z]|[0-9])*$

0
 
LVL 64

Expert Comment

by:Fernando Soto
ID: 17033849
Actually the $ lets the regular expression engine know that there should be no more characters. If you do not place it there then you could have invalid characters at the end and as long as the string starts with an alpha followed by 1 or more alpha numeric it will validate.
0
 
LVL 18

Expert Comment

by:Ravi Singh
ID: 17034059
thanks Fernando... I tested it with some leading spaces and mistakenly wrote that... your explanation covers what I was trying to say!
0
 
LVL 64

Expert Comment

by:Fernando Soto
ID: 17036940
Good; glad we are on the same track. You have a great day. :=)
0

Featured Post

Free Tool: Subnet Calculator

The subnet calculator helps you design networks by taking an IP address and network mask and returning information such as network, broadcast address, and host range.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This article introduced a TextBox that supports transparent background.   Introduction TextBox is the most widely used control component in GUI design. Most GUI controls do not support transparent background and more or less do not have the…
The article shows the basic steps of integrating an HTML theme template into an ASP.NET MVC project
Exchange organizations may use the Journaling Agent of the Transport Service to archive messages going through Exchange. However, if the Transport Service is integrated with some email content management application (such as an anti-spam), the admin…
Is your data getting by on basic protection measures? In today’s climate of debilitating malware and ransomware—like WannaCry—that may not be enough. You need to establish more than basics, like a recovery plan that protects both data and endpoints.…
Suggested Courses
Course of the Month16 days, 7 hours left to enroll

850 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question