alphanumeric regular expression needed

Use a pattern like this:

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

(^-?[a-zA-Z0-9]*$)

this should do it

jimbona27,

Please clarify what you mean by "alphanumeric".

For example, my pattern will reject the following:

<zero length string>
-
-1
-a
-234xyz

brad2575's pattern will accept all of them...

Patrick

(^-?[a-zA-Z0-9]*$) should be the one.

For more about regular expressions, check out:
http://www.regular-expressions.info

It contains a similar example as well. Check out:
http://www.regular-expressions.info/numericramges.html

Hope it helps.

Actually, for my last post, a slight modification would be needed to validate that the string was alpha-numeric:

[^a-zA-Z0-9]+

<asp:RegularExpressionValidator ID="RegularExpressionValidator1" runat="server" 
    ErrorMessage="Please enter an alpha-numeric string" ControlToValidate="TextBox1" 
    ValidationExpression="[^a-zA-Z0-9]+"></asp:RegularExpressionValidator>
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>

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Hi jimbona27,
You can also use "\w+" to check that all characters are alphanumeric.

This is a tutorial that I found very helpful:
http://www.codeproject.com/KB/dotnet/regextutorial.aspx

You can also download the expresso regex application which is based on .NET technology (i.e. like c#).

Hope this helps.
P.

use @"\w+" to string escape it.
P.

\w

also matches underscore, which the OP may not want  :)

My previous post contains error in some input samples.

Try the below expression:

^\\w+[^_]$

Hope this will work.



-Shahan

^\\w+[^_]$

will match:

    abc_def
    _1

@ kaufmed

You posted this regular expression & ASP.NET code for its use
[^a-zA-Z0-9]+


  1) ASDV09asd
       this is treated as non-alphanumeric. I could not understand ????

I was testing the patterns from here:

http://derekslager.com/blog/posts/2007/09/a-better-dotnet-regular-expression-tester.ashx

@Shahan_Developer

I was thinking at the time that RegularExpressionValidator displayed its error message if the pattern was successful, not if it failed. It seems the latter is correct--good catch Shahan_Developer. The first post, 30658606, would be the proper usage.

@ kaufmed

In your post, 30658606, your approach seems to be correct but still getting unexpected result.

In your post, 30658606 you are right mistake is from my side.

Thanks kaufmed,
I didn't know that the underscore was treated as part of the alphanumeric type, anyhow, I just wanted to post the corrected other way for matching:

@"^[\w-[_]]+$"

This will work too.
P.