Limiting entry to numeric characters for a textbox

I want to limit entry into a text box to numeric characters (
Anthony MatovuBusiness Analyst, MTN UgandaAsked:
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1) Declare a variable to hold JavaScript for enabling only Numbers as follows:
Dim strNumberOnlyValidation As String = "if (event.keyCode < 48 || event.keyCode > 57) event.returnValue = false;"

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2) Link the above JavaScript Variable to the requested TextBox as follows in Page_Load:
MyTextBox.Attributes("onKeypress") = strNumberOnlyValidation

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You may find a list of JavaScript KeyCodes here:
Kiran SonawaneProject LeadCommented:
Like this

<asp:TextBox runat="server" id="txtNumber" />
<asp:RegularExpressionValidator runat="server" id="rexNumber" controltovalidate="txtNumber" validationexpression="^[0-9]+$" errormessage="Please enter digit only!" />


<asp:TextBox runat="server" id="txtNumber" />
<asp:RegularExpressionValidator runat="server" id="rexNumber" controltovalidate="txtNumber" validationexpression="\d+" errormessage="Please enter digit only!" />
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Try This:
<asp:RegularExpressionValidator runat="server" id="rexNumber"
            controltovalidate="txtSN1" validationexpression="(^-?\d\d*\.\d*$)|(^-?\d\d*$)|(^-?\.\d\d*$)" errormessage="Please enter digit only!" />
Anthony MatovuBusiness Analyst, MTN UgandaAuthor Commented:
Sorry, it is a windows application, not an application
thank you
Kiran SonawaneProject LeadCommented:
Try this

Private Function TrapKey(ByVal KCode As String) As Boolean
   If (KCode >= 48 And KCode <= 57) Or KCode = 8 Then
       TrapKey = False
       TrapKey = True
    End If
End Function

Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
        e.Handled = TrapKey(Asc(e.KeyChar))
End Sub

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Visual Basic.NET

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