Only accept letters, numbers and underscores in a textbox

[Markus_Urban]

Hi!
I am creating a new app and in the username textbox I only want to allow letters, numbers and underscores. How can I do that?
Thanks for your help!

[Business_World]

me my friend use this. in @ place you type which letter you dont want

[Markus_Urban]

It’s a nice idea!
But there are so many characters that I don’t want the users to enter…
Do you know another way that uses the characters that the users can enter?
Thank you very much

[Business_World]

you make many blocks so many not allow letter

[Boban (Boban Stojmenovic)]

Use regex, I think you can try the aia from this thread

Unicode in text box

Try this one TextRegexTest.aia (7.5 KB)

[Markus_Urban]

Hi!
I used Regex in other project, and it worked very well, but I don’t know how to let the user also use underscores

[Boban (Boban Stojmenovic)]

You are lucky, I just opened the project

Pattern what is allowed [^a-zA-Z 0-9/@%!"#?¨’_.,]

[Markus_Urban]

Thank you very much!
I was just looking in the Regex website. Thank you very much for the pattern!

[Markus_Urban]

Thank you very much for your answer!
Now i’m gonna use the regular expressions, but I appreciate very much your answers.
Have a nice day!