达到 MaxLength 时 XAML 触发自动制表符

Question

当 MaxLength 属性到达 XAML 触发器、DataTrigger、PropertyTrigger、Style.Trigger 等时，如何合并自动制表符。下面是两个这样的选项，说明我如何通过代码隐藏使用 TextBox 完成此操作。我也希望将其应用到 XAML 样式中。谢谢。

XAML：

<TextBox x:Name="MyTextBox"
            Text="{Binding Path=MyProperty}"
            Style="{StaticResource TextBoxStyle}"
            MaxLength="5"
            TextChanged="MyTextBox_TextChanged">
</TextBox>

WPF 的代码隐藏：

private void MyTextBox_TextChanged(object sender, TextChangedEventArgs e)
{
    if (MyTextBox.Text.Length == MyTextBox.MaxLength)
    {
        Keyboard.Focus(NextTextBox);
    }
}

private void MyTextBox_PreviewKeyDown(object sender, KeyEventArgs e)
{
    // Auto-tab when maxlength is reached
        if (((TextBox)sender).MaxLength == ((TextBox)sender).Text.Length)
        {
            // move focus
            var ue = e.OriginalSource as FrameworkElement;
            e.Handled = true;
            ue.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
        }
    }
}

Answer 1

只需在 Shell.xaml

 <Style TargetType="TextBox">
                <EventSetter Event="TextChanged" Handler="MyTextBox_PreviewKeyDown"/>
            </Style>

和 shell.xaml.cs 中执行此操作

private void MyTextBox_PreviewKeyDown(object sender, KeyEventArgs e)
{
    // Auto-tab when maxlength is reached
        if (((TextBox)sender).MaxLength == ((TextBox)sender).Text.Length)
        {
            // move focus
            var ue = e.OriginalSource as FrameworkElement;
            e.Handled = true;
            ue.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
        }
    }
}