How to filter textbox input to numeric only?

Question

How do I suppress all data except numeric?

This is not working on KeyDown():

If e.KeyData < Keys.D0 Or e.KeyData > Keys.D9 Then
    e.Handled = True
End If

I think you can find your answer here: http://stackoverflow.com/questions/463299/how-do-i-make-a-textbox-that-only-accepts-numbers (don't miss to pay attention to the comment by Jeff Yates) — Fredrik Mörk, Jun 02 '09 at 07:39

score 6 · Answer 1 · answered Jun 02 '09 at 08:12

There are many ways to do this. I've had a quick stab at it and go this which works. I have used the KeyPress sub for the textbox, and pass each keypress to the IsNumber function.

NOTE: I have allowed the backspace key to be used in case you make a mistake with the numbers and want to deleted.

Take out the If e.KeyChar <> ChrW(Keys.Back) Then / End If part if you dont need the backspace.

    Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
    If e.KeyChar <> ChrW(Keys.Back) Then
        If Char.IsNumber(e.KeyChar) Then
        Else
            e.Handled = True
        End If
    End If
End Sub

What about the delete key? What about cut and paste from the clipboard? — Chris Dunaway, Jun 02 '09 at 22:35
Certainly, they could be added into the IF statement to ignore. Good Point. — kevchadders, Jun 04 '09 at 07:49

score 4 · Accepted Answer · edited Jun 10 '14 at 16:21

4

You can check Char.IsDigit(e.KeyChar), but the best thing to do in this case is to create a subclass of TextBox and override IsInputChar(). That way you have a reusable TextBox control that you can drop anywhere so you don't have to re-implement the logic.

(My VB is a bit rusty...)

Public Class NumericTextBox : Inherits TextBox

    Protected Overrides Function IsInputChar(Byval charCode As Char) As Boolean
        If (Char.IsControl(charCode) Or Char.IsDigit(charCode)) Then
            Return MyBase.IsInputChar(charCode)
        Else
            Return False
        End If
    End Function

End Class

edited Jun 10 '14 at 16:21

Anonymous Pi

125
7

answered Jun 02 '09 at 07:42

Josh

68,005
14
144
156

Don't forget to allow (localized) thousand and decimal separators – Fredrik Mörk Jun 02 '09 at 07:57
Will this handle cases where the text is pasted in from the clipboard? – Chris Dunaway Jun 02 '09 at 22:35

score 1 · Answer 3 · answered Apr 11 '12 at 03:23

This code will help you to restrict multiple TEXTBOX to accept only NUMERIC VALUE and BACKSPACE key. However you can remove If e.KeyChar <> ChrW(Keys.Back) Then and End If value from code when you don't want to accept backspace key. Enhanced version of the kevchadders solution in this thread.

Private Sub TextBox_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress, TextBox2.KeyPress, TextBox3.KeyPress
    If e.KeyChar <> ChrW(Keys.Back) Then
        If Char.IsNumber(e.KeyChar) Then
        Else
            e.Handled = True
        End If
    End If
End Sub

Duke49ifrance · Answer 4 · 2013-06-22T22:36:45.097

Will help you...

    Public Function IsNumericTextbox(ByVal sender As TextBox, ByVal KeyChar As Char) As Boolean
    'set TRUE: cause a exception when the keychar is not Allowed into vars: allowedChars, allowedOneChar, allowedExceptionChar
    Dim UseThrowDebuggy As Boolean = False

    Dim allowedChars As String = "0123456789"
    Dim allowedOnceChar As Char() = {"."}
    Dim allowedExceptionChar As Keys() = {Keys.Back}

    Dim idxAllowedNotFound As Integer
    Dim idxCountOne As Integer = 0

    idxAllowedNotFound = allowedChars.IndexOf(KeyChar)
    If idxAllowedNotFound = True Then
        'AllowedOnce
        For Each _c As Char In allowedOnceChar
            If _c = KeyChar Then
                'Count Check
                For Each _cc As Char In sender.Text
                    If _c = _cc Then idxCountOne += 1
                Next
                If idxCountOne = 0 Then
                    Return False
                Else
                    Return True
                End If
            End If
        Next
        'Exceptions
        For i As Integer = 0 To allowedExceptionChar.Count - 1
            If Asc(KeyChar) = Convert.ToUInt32(allowedExceptionChar(i)) Then Return False
        Next
        'Not Throw
        If UseThrowDebuggy = False Then
            If Char.IsNumber(KeyChar) Then
                Return False
            Else
                Return True
            End If
        End If
        'Outside to end for throw
    Else
        'AllowedChars
        Return False
    End If

    Dim _kc As String = ControlChars.NewLine & "Char: " & KeyChar & ControlChars.NewLine & "Asc: " & Asc(KeyChar) & ControlChars.NewLine
    Throw New Exception("UseThrowDebuggy found a unknow KeyChar: " & _kc)
End Function

For use my function add this code into a textbox_keypress:

e.Handled = IsNumericTextbox(sender, e.KeyChar)

score 1 · Answer 5 · answered Nov 23 '14 at 14:46

 Public Class NumericTextBox : Inherits System.Windows.Forms.TextBox

 Protected Overrides Sub OnKeyPress(e As Windows.Forms.KeyPressEventArgs)
      If Char.IsDigit(e.KeyChar) Or
          Char.IsControl(e.KeyChar) Or
          e.KeyChar = lobalization.CultureInfo.CurrentCulture.NumberFormat.CurrencyDecimalSeparator Then
      MyBase.OnKeyPress(e)
    Else
        e.Handled = True
    End If
 End Sub

 End Class

score 0 · Answer 6 · answered Mar 28 '13 at 10:48

This will allow numeric input ,Backspace to correct your input , and also a decimal point.

    If (e.KeyChar < "0" OrElse e.KeyChar > "9") AndAlso e.KeyChar <> ControlChars.Back AndAlso e.KeyChar <> ControlChars.Cr AndAlso e.KeyChar <> "." Then
        Beep()
        e.Handled = True
    End If

score 0 · Answer 7 · answered Jun 22 '13 at 11:50

This is another way to restrict number inputs into textbox . using KEYPRESS Events

If Asc(e.KeyChar) <> 13 AndAlso Asc(e.KeyChar) <> 8 AndAlso Not IsNumeric(e.KeyChar) Then MessageBox.Show("Only Numbers") e.Handled = True End If End Sub hope it helps ! thnks ..

score 0 · Answer 8 · answered Jun 16 '16 at 16:08

The purpose of your function could help provide additional solutions. Checking for a numeric value on each KeyPress is likely overkill. Then you have to overkill it more by accounting for backspace, delete, copy, paste, etc.

For example, if you are storing a telephone number, you should use the "IsNumeric" function on the validate and update step. Alternatively, if you are selecting quantity of an item "NumericUpDown" control would be more appropriate than a TextBox.

score 0 · Answer 9 · edited Jun 21 '12 at 13:02

I suggest that you use regular expressions. You can search Google, like 'regular expression textbox only numeric' and I guess you'll come up with many examples.

For example, if you are in ASP.NET you can do it like:

<asp:TextBox 
    ID="txtPhoneNumber" 
    runat="server" 
    Text='<%#Bind("phoneNumber") %>' 
    MaxLength="15">
</asp:TextBox>

<asp:RegularExpressionValidator 
    ID="rfvUSerPhoneNumberValidate" 
    runat="server"
    ControlToValidate="txtPhoneNumber" 
    Display="Dynamic" 
    ValidationExpression="^[0-9]{1,15}$"
    ErrorMessage="Please enter only numeric value for Phone Number" 
    EnableViewState="true">
</asp:RegularExpressionValidator>

How to filter textbox input to numeric only?

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