numerictextbox.vb

清华大学出版社出版的 移动应用开发宝典 张大威（2008）的附书源代码

Public Class NumericTextBox
    Inherits TextBox

    Private blockedKey As Boolean = False

    Protected Overrides Sub OnKeyDown(ByVal e As KeyEventArgs)
        Me.blockedKey = False
        If (e.Shift OrElse e.Alt) Then
            Me.blockedKey = True
        ElseIf ((((e.KeyCode < Keys.D0) OrElse (e.KeyCode > Keys.D9)) AndAlso ((e.KeyCode < Keys.NumPad0) OrElse (e.KeyCode > Keys.NumPad9))) AndAlso (e.KeyCode <> Keys.Back)) Then
            Me.blockedKey = True
        End If
    End Sub

    Protected Overrides Sub OnKeyPress(ByVal e As KeyPressEventArgs)
        If Me.blockedKey Then
            e.Handled = True
        End If
    End Sub

End Class