学步园

用PreviewKeyDown事件和KeyEventArgs.Handled 来实现

示例：限制了只能输入1和退格键

XAML

<TextBox HorizontalAlignment="Left" Margin="0,60,0,0" Name="textBox1" Width="120" Height="22" VerticalAlignment="Top"  PreviewKeyDown="textBox1_PreviewKeyDown" />

 

C#

private void textBox1_PreviewKeyDown(object sender, KeyEventArgs e)
        {
            if (e.Key != Key.D1 && e.Key != Key.Back && e.Key !=Key.NumPad1)
            {
                e.Handled = true;
            }
        }