Private Sub textBox_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles textBox.KeyPress
 
        If Char.IsNumber(e.KeyChar) Or Asc(e.KeyChar) = 8 Then
            e.Handled = False
        Else
            e.Handled = True
            MsgBox("Numeric Values Only", MsgBoxStyle.OkOnly + MsgBoxStyle.Information, "Input Error")
        End If
 
End Sub

Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
    If (Microsoft.VisualBasic.Asc(e.KeyChar) < 48) _
              Or (Microsoft.VisualBasic.Asc(e.KeyChar) > 57) Then
            e.Handled = True
    End If
    If (Microsoft.VisualBasic.Asc(e.KeyChar) = 8) Then
            e.Handled = False
    End If
End Sub

        If Char.IsNumber(e.KeyChar)Then
 
        Else
            MsgBox("Numeric Values Only", MsgBoxStyle.OkOnly + MsgBoxStyle.Information, "Input Error")
        End If

        Dim err As Integer = 0
        If InStr(CharactersAllowed, e.KeyChar.ToString.ToUpper) = 0 Then
            err = 1
            If enter And Asc(e.KeyChar) = Keys.Enter Then err = 0
            If BackSpace And Asc(e.KeyChar) = Keys.Back Then err = 0
            If Asc(e.KeyChar) = 3 Then err = 0
            If Asc(e.KeyChar) = 22 Then err = 0
        End If
        If err = 1 Then
            e.Handled = True
        End If
    End Sub