Allow only 20 alphabets and numbers in TextBox using regular expression.

zohaib khan

Hi,

I have TextBox and I want to add validation using regular expression.

I want to allow only 20 alphabet or number in TextBox.

Example [A-Za-z0-9]{1,20}

Any idea about regular expression.

- Thanks

8 Replies

Know the answer? Post it — somebody with the same question will find it here.

Vulpes14y ago
Accepted answer
\p{IsArabic} should match any Arabic character.

So, if you want to mix these in with English characters and spaces (subject to a maximum of 20 characters overall), I'd try:

@"^[\p{IsArabic}a-zA-Z\s]{1,20}$"

or if you want to precede the (maximum 20) English characters and spaces by any number of Arabic characters (including 0):

@"^\p{IsArabic}*[a-zA-Z\s]{1,20}$"
zohaib khan14y ago
Hi Vulpes,

Excellent many thanks.

Zohaib.
zohaib khan14y ago
Hi,

Any idea about regular expression if I use English and Arabic with following

@"^[a-zA-Z\s]{1,20}$"

I tried

@"^[?-?\s]*[a-zA-Z\s]{1,20}$" but not working

Unicode Regular Expressions will help?
http://www.regular-expressions.info/unicode.html#script

- Thanks
zohaib khan14y ago
Thanks Valpes

It is working :)
Vulpes14y ago
If you only want to allow extra spaces at the end, use:

string regExp = @"^[a-zA-Z0-9]{1,20}\s*$";

If you want to allow spaces anywhere within the string but limited overall to 20 characters, use:

string regExp = @"^[a-zA-Z0-9\s]{1,20}$";
zohaib khan14y ago
Thanks for reply.

it is working and if I want to allow spaces adding + sign not working.

^[A-Za-z]{1,20}+$

OR

^[A-Za-z\s]{1,20}$

I am getting exception regarding - Nested quantifier +.
14y ago
Can you please try this ?

[a-zA-Z0-9]{20}

Online RegEx tester
Vulpes14y ago
Try the following regular expression:

string regExp = "^[a-zA-Z0-9]{1,20}$";

Allow only 20 alphabets and numbers in TextBox using regular expression.

Unicode Regular Expressions will help?