WPF中Textbox获取TextChanged事件+键盘事件+右击菜单栏

键盘响应代码：

private void textBox_KeyDown(object sender, KeyEventArgs e)
{
    string strMessage = "textBox_KeyDown Event:" + e.RoutedEvent + "  " + "Key:" + e.Key;
    if(listBox!=null)
        {
            listBox.Items.Add(strMessage);
        }
}

textBox内容变更消息响应代码：

private void textBox_TextChanged(object sender, TextChangedEventArgs e)
{
    string strMessage = "textBox_TextChanged Event:" + e.RoutedEvent;
    if(listBox!=null)
    {
        listBox.Items.Add(strMessage);
    }
}

显示右键菜单代码：

private void listBox_MouseRightButtonDown(object sender, MouseButtonEventArgs e)//右击弹出菜单
{
    ContextMenu aMenu = new ContextMenu();
    MenuItem deleteMenu = new MenuItem();
    deleteMenu.Header = "清空";
    deleteMenu.Click += btDel_Click;
    aMenu.Items.Add(deleteMenu);
    listBox.ContextMenu = aMenu;
}
private void btDel_Click(object sender, RoutedEventArgs e)
{
    listBox.Items.Clear();
}

界面的Xmal代码：

<Grid>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="74*"/>
        <ColumnDefinition Width="445*"/>
    </Grid.ColumnDefinitions>
    <Grid.RowDefinitions>
        <RowDefinition Height="30*"/>
        <RowDefinition Height="263*"/>
    </Grid.RowDefinitions>
    <TextBlock x:Name="textBlock" HorizontalAlignment="Left" TextWrapping="Wrap" Text="请输入：" TextAlignment="Center" VerticalAlignment="Center" Grid.Row="0" Margin="0,7,0,6.6"/>
    <TextBox x:Name="textBox" Grid.RowSpan="1" TextWrapping="Wrap" Text="TextBox" Grid.Column="1" VerticalAlignment="Center" KeyDown="textBox_KeyDown" TextChanged="textBox_TextChanged"/>
    <TextBlock x:Name="textBlock2" HorizontalAlignment="Left" TextWrapping="Wrap" Text="事件记录：" TextAlignment="Center" VerticalAlignment="Center" Grid.Row="1" Margin="0,6.4,0,5.6"/>
    <ListBox x:Name="listBox" Grid.Row="1" Grid.Column="1" Margin="0,0.4,0.4,-0.2" MouseRightButtonDown="listBox_MouseRightButtonDown"/>
</Grid>