Public Class OnlyNumericTextbox
    Inherits TextBox
    Public Sub New()
    End Sub
    Private Sub DoCheck(ByVal sender As Object, ByVal e As EventArgs) Handles Me.TextChanged
        If Me.Text.Length > 0 Then
            Dim newstr As String = ""
            Dim i As Integer
            For i = 0 To (Me.Text.Length - 1)
                If Me.Text.Substring(i, 1) >= "0" And Me.Text.Substring(i, 1) <= "9" Then
                    newstr = newstr + Me.Text.Substring(i, 1)
                End If
            Next
            Me.Text = newstr
        End If
    End Sub
End Class