Alphanumeric is a combination of alphabetic and numeric characters.The alphanumeric character set consists of the numbers 0 to 9 and letters A to Z. for example these are the alphanumeric:
1. Author123
2. author5Code
3. 123456TY
4. 897AUTOR
suppose if you want to know that particular string is a alphanumeric or not than you can use following code sample
[VB.Net]
Private Function IsAlphaNum(ByVal strInputText As String) As Boolean return System.Text.RegularExpressions.Regex.IsMatch(strInputText, "^[a-zA-Z0-9]+$") End Function
[C#]
private bool IsAlphaNum(string strInputText) { return System.Text.RegularExpressions.Regex.IsMatch(strInputText, "^[a-zA-Z0-9]+$"); }
This code is horrible, it doesn’t even come close to meeting the goals of this simple function. For example “123” is not Alpha Numeric? How about “AA-&^^^%%-12”?
wow just came across this code – ouch
if you want an alphanumeric checker you need
// ans – (a)lpha (n)umeric (s)tring is our flag to see if it is or isnt
dim ans as boolean = true
For i = 0 To str.Length – 1
//if you need to include spaces you needto add ‘ or str(i) = ” ” ‘ to the next line – please note that this is not a secure method for cleansing strings just a quick hack around the example!
If not Char.IsLetter(str(i)) or Char.IsNumber(str(i)) Then
ans = false
End If
Next
if ans = true
//yey its alphanumeric
else
//boo it isnt
end if
Ooops – you should also exit the loop
so after “ans = false”
put
“exit for”
otherwise you are wasting processor time.
Wow this is the worst function ever, seriously this should be deleted, cant believe this pile of crap came up number 1 on google for my search, useless
Now we are using the regular expression to check the string is alphanumeric or not..
Be simpler to just return System.Text.RegularExpressions.Regex.IsMatch(strInputText, “^[a-zA-Z0-9]+$”) rather than declaring the variable, initializing it to a value that is never used, and then having an IF.
Thank you for sharing. Code is updated.
How to validate input.. 1 item string followed by 4 digits