Number Only Input

Number Only Input

• j2associates

  If you're parsing yourself for the number, throw away the maskedtextbox :)

  Yes, it's completely possible. In the event where you're testing to see if it parses as a number, you just need to modify the contents of the textbox.

  Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged

    If Int32.TryParse(TextBox1.Text, Nothing) = False Then

      TextBox1.Text = TextBox1.Text.Substring(0, TextBox1.Text.Length - 1)

    End If

  End Sub

  Of course, is this what you want What if the user had clicked back to the start of the text and added a character at the start of the textbox What if they typed something in the middle of the string

  
  
  

• sk78

  Yeah, you could, you just need to keep track of it yourself (.net won't tell you what the change was, just that the text was changed:

  Private mLastValue as String

  Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged

    If Int32.TryParse(TextBox1.Text, Nothing) = False Then

      TextBox1.Text = mLastValue

    Else

      mLastValue = TextBox1.Text

    End If

  End Sub

  
  
  

• VolcanoDan

  lol that's cool. Thanks anyways. You've been a great help.
  

• David Salvi

  Ok. That's not rlly how I want it. sorry. Normally i wouldn't bother and i'd just leave it but i am doing this for a bit of a learning exercise. I've already got some code being triggered when the text changes and in that code i've got it checking wether it can parse it as an integer. now if it doesn't i would like it to delete the last character that was entered. is this possible
  

• James 1375

  There is a magic line of code like below :
  <asp:textbox onkeypress="if ((event.keycode <48) || (event.keycode > 57)) event.returnvalue=false" id=postcode runat=server></asp:textbox>
  
  

• Simplify

  yeah that's what i meant. Could you remove the last entered character. not the character at the end of the string. If you don't know how to do this that's cool. I am just nit picking. Like i said they only reason i haven't given up on it yet is because this is a learning exercise and i was just curious.
  

• _Rob_

  Just write some javascript and add it to the attributes of the text box:
  
  txtInput.Attributes.Add("OnKeyPress", "CheckNumberic()")
  
  

• Benedictum

  No, but you _can_ have it only visible when the textbox has the focus - will that do

  You just need to set the HidePromptOnLeave() property to True. It's a stupid name, but it's probably the best you'll get.

  Edit: You could also look at the TextMaskFormat property, which, according to the doco 'Gets or sets a value that determines whether literals and prompt characters are included in the formatted string'

  
  
  

• RCR

  Hi,

  If it is in web page you can go for valitation controls. If it is in windows form you can get the input from the user and validate for 0-9 by using ASCII comparison.

   

  Regards,

  venkataraman.R

  
  

• VCBeginer

  Wait i've figured something out. If you could tell me a way to set the position of the cursor then it will be perfect and i'll post the code.

  EDIT:I meant the position of the cursor in the textbox. not the mouse cursor

  
  

• Igal Chariski

  Sorry, you've reached the end of my knowledge :(
  
  

• Daniel Horowitz

  Thanks geoff. That's what I was looking for. Thanks to everyone else for trying as well but this is the solution that suited me better and it needed to be for vb. One more question. Is there anyway to get rid of that black line thats at the bottom of the textbox Thanks

  EDIT: I figured out hwo to change the prompt character. I tried changing it to a space but it of course leaves spaces in the text box. So, is there anyway to just like disbale prompting

  
  

• Richard Drysdall

  Hi,

  There's no magic 'one line of code' that will do it for you, but it's very easy to build your own input box - it's just a new form with a text box, and OK and Cancel buttons.

  Since you're using the UI, instead of validating the string yourself (which you could do as in the previous answer), you could also look into using the MaskedTextBox. The Mask() property of this control allows you define a mask for how text is input. If, say, you only want to allow 10 digit numbers, you simply set a mask of 10 '0's and .net will take care of the rest.

  HTH

  
  
  

• Lepsik

  There isn't already done but you can create in a very simple way... could use validator or simply check text in textbox (it must be only "Digit", so you check Char.isDigit(char c )   ).

  You can check char after char or check the whole string (i prefer this)

  string pippo;

  foreach(char c in pippo){

  if(!Char.IsDigit(c))

  //Console.Write("Errore");

  }

   

  sorry it's wrong forum...it's in c#..if it can help you...

  
  
  
• Number Only Input