How can I force a user to enter a string with characters only with no integer from a text box?

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Hi,

I have textbox that takes only a fully characters string for example person name. If the user enter something like (paul123) or (1234), it should get an invalid input.

I try this:

Integer.parse(me.nametextbox.text)
msgbox("invalid")
me.nametextbox.lostfocus

It works when the user types an integer first, it gives the message but user types a character first it goes through - that is not what I want.

Any idea?

Best Regards

Posted 14-Aug-09 6:45am

waner michaud

Updated 25-Aug-09 10:33am

Sean Ewington

v2

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4 solutions

Solution 3

Try This Private Sub me.nametextbox_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles me.nametextbox.KeyPress If (Not (Char.IsDigit(e.KeyChar) Or Char.IsControl(e.KeyChar))) Then e.Handled = True : MsgBox("Please enter valid Char.", MsgBoxStyle.Information, "Message") End If End Sub

Posted 25-Nov-09 0:22am

vijaykumarpatel

v2

Solution 4

"[0-9]"

That regular expression will find any digit in a string. So, what you want to do is check the string to see if that regular expression returns any results. If it does, that means the string contains a digit. I don't want to make it too easy for you (as I expect you to do the learning and only come to us when you are running into a problem you can't seem to solve), so I will leave figuring out how to use the regular expression up to you. This should get you started: .Net Regular Expressions.

Alternatively, you could just loop through each character in the string and check if it is a digit. Again, that should be extremely simple, so I'll leave that as an exercise for you to do.

Posted 25-Nov-09 0:49am

AspDotNetDev

Solution 2

Thanks,

Can You provide me with an example of relax expression and how to apply?

Thanks again

Posted 14-Aug-09 11:41am

waner michaud

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Dave Kreskowiak · Accepted Answer · 2009-08-14T07:42:00

Solution 1

It's possible that the test is being interpreted as a hexadecimal number. Instead of using TryParse to determine if it's a good number, use a regular expression instead.

Posted 14-Aug-09 7:42am

Dave Kreskowiak