我认为最干净的方法是在数据级别而不是在UI中处理。显然，CheckBox状态影响数据，而不仅仅是视觉表示。
根据您的上下文，您可以使用数据绑定或ICommand来触发数据源相应地更新其属性：

方案一

使用数据绑定并将CheckBox.IsChecked绑定到数据源。
另外，直接绑定TextBox.IsEnabled消除了DataTrigger，以进一步简化代码：

主窗口。xaml

<Window>
  <Window.DataContext>
    <DataSource /> 
  </Window.DataContext>

  <Stackpanel>
    <CheckBox IsChecked="{Binding IsSaveNameEnabled}" />
    <TextBox Text="{Binding Name}"
             IsEnabled="{Binding IsSaveNameEnabled}" />
  </StackPanel>
</Window>

DataSource。cs

// For simplicity the properties don't raise the INotifyPropertyChanged.PropertyChanged event
class DataSource : INotifyPropertyChanged
{
  private bool isSaveNameEnabled;
  public bool IsSaveNameEnabled 
  { 
    get => this.isSaveNameEnabled; 
    set
    {
      this.isSaveNameEnabled = value;
      OnPropertyChanged();
      OnIsSaveNameEnabledChanged();
    }
  }

  public string Name { get; set; }

  private void OnIsSaveNameEnabledChanged()
  {
    if (!this.IsSaveNameEnabled)
    {
      // Alternatively, instead of clearing the value
      // use the flag to explicitly ignore the related 
      // data value when persisting the data.
      // In this case the TextBox would show a greyed-out value.
      this.Name = string.Empty;
    }
  }
}

方案二

使用命令执行数据源中的数据相关逻辑。
同样，绑定TextBox.IsEnabled直接消除了DataTrigger，以进一步简化代码。
该示例使用ICommand的RelayCommand实现。
您可以在Microsoft Docs中找到此类的源代码：继电器命令逻辑：

主窗口。xaml

<Window>
  <Window.DataContext>
    <DataSource /> 
  </Window.DataContext>

  <Stackpanel>
    <CheckBox x:Name="DisableTextInputButton" 
              Command="{Binding IgnoreNameValueCommand}" 
              CommandParameter="{Binding RelativeSource={RelativeSource Self}, Path=IsChecked}" />
    <TextBox Text="{Binding Name}"
             IsEnabled="{Binding ElementName=DisableTextInputButton, Path=IsChecked}" />
  </StackPanel>
</Window>

DataSource。cs

// For simplicity the properties don't raise the INotifyPropertyChanged.PropertyChanged event
class DataSource : INotifyPropertyChanged
{
  public RelayCommand IgnoreNameValueCommand { get; }
    = new RelayCommand(ExecuteIgnoreNameValueCommand, CanExecuteIgnoreNameValueCommand);

  public string Name { get; set; }

  private bool CanExecuteIgnoreNameValueCommand(object commandParameter)
    => commandParameter is bool;

  private void ExecuteIgnoreNameValueCommand(object commandParameter)
  {
    bool isSaveNameEnabled = (bool)commandParameter;
    if (!isSaveNameEnabled)
    {
      // Alternatively, instead of clearing the value save the isSaveNameEnabled value
      // in a property and use it later to explicitly ignore the related 
      // data value when persisting the data.
      // In this case the TextBox would show a greyed-out value.
      this.Name = string.Empty;
    }
  }
}

您遇到的问题是，使用<Setter Property="Text" Value="{x:Null}" />时，您会从ViewModel中删除与属性的绑定。
再次启用TextBox后，另一个样式Setter将再次将绑定设置为VM中未修改的值。财产。
你能做的就是在e中设置值。一种行为：

<TextBox x:Name="tb1" Margin="5" Text="{Binding Path=SomeStr, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity">
    <i:Interaction.Behaviors>
        <yourBehaviorsXmlns:EmptyOnDisabled/>
    </i:Interaction.Behaviors>
    <TextBox.Style>
        <Style TargetType="{x:Type TextBox}">
            <Style.Triggers>
                <DataTrigger Binding="{Binding ElementName=SomeCheckBox, Path=IsChecked}" Value="False">
                    <Setter Property="IsEnabled" Value="False" />
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </TextBox.Style>
</TextBox>

public class EmptyOnDisabled : Behavior<TextBox>
{
    protected override void OnAttached()
    {
        base.OnAttached();
        AssociatedObject.IsEnabledChanged += AssociatedObject_IsEnabledChanged;
    }

    private void AssociatedObject_IsEnabledChanged(object sender, DependencyPropertyChangedEventArgs e)
    {
        if (!AssociatedObject.IsEnabled)
        {
            AssociatedObject.Text = null;
        }
    }

    protected override void OnDetaching()
    {
        base.OnDetaching();
        AssociatedObject.IsEnabledChanged -= AssociatedObject_IsEnabledChanged;
    }
}

另一种方法是使用附加属性，如果它应该在其他条件下完成。更好的方法是在viewmodel中进行，在那里你应该存储复选框的状态。

<TextBox Margin="5" x:Name="tb1" attachedProps:ClearTextAttached.DontClearText="{Binding ElementName=SomeCheckBox, Path=IsChecked}">
    <TextBox.Style>
        <Style TargetType="{x:Type TextBox}">
            <Setter Property="Text" Value="{Binding Path=SomeStr, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
            <Style.Triggers>
                <DataTrigger Binding="{Binding ElementName=SomeCheckBox, Path=IsChecked}" Value="False">
                    <Setter Property="IsEnabled" Value="False" />
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </TextBox.Style>
</TextBox>

public class ClearTextAttached
{
    public static bool GetDontClearText(DependencyObject obj)
    {
        return (bool)obj.GetValue(DontClearTextProperty);
    }

    public static void SetDontClearText(DependencyObject obj, bool value)
    {
        obj.SetValue(DontClearTextProperty, value);
    }
        
    public static readonly DependencyProperty DontClearTextProperty =
        DependencyProperty.RegisterAttached("DontClearText", typeof(bool), typeof(ClearTextAttached), new PropertyMetadata(false, ClearTextChanged));

    private static void ClearTextChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        if (d is TextBox tbx && !(bool)tbx.GetValue(ClearTextAttached.DontClearTextProperty))
        {
            tbx.Text = null;
        }
    }
}