Question

在WPF中有一种简单的方法可以将VisualStates绑定到枚举值吗？有点像DataStateBehavior，但对于Enum？

Answer 1

最好的方法是继续实施一个行为 -

public class EnumStateBehavior : Behavior<FrameworkElement>
{
    public object EnumProperty
    {
        get { return (object)GetValue(EnumPropertyProperty); }
        set { SetValue(EnumPropertyProperty, value); }
    }

    // Using a DependencyProperty as the backing store for EnumProperty.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty EnumPropertyProperty =
        DependencyProperty.Register("EnumProperty", typeof(object), typeof(EnumStateBehavior), new UIPropertyMetadata(null, EnumPropertyChanged));

    static void EnumPropertyChanged(object sender, DependencyPropertyChangedEventArgs e)
    {
        if (e.NewValue == null) return;

        EnumStateBehavior eb = sender as EnumStateBehavior;

        VisualStateManager.GoToElementState(eb.AssociatedObject, e.NewValue.ToString(), true);
    }

}

使用非常简单 - 使用方法如下：

<i:Interaction.Behaviors>
        <local:EnumStateBehavior EnumProperty="{Binding MyEnumProperty}" />
</i:Interaction.Behaviors>

Answer 2

你可以在纯xaml中使用DataTrigger每个可能的枚举值，每个触发器调用不同状态的GoToStateAction。请参阅下面的示例。有关详细信息，请查看 Enum driving a Visual State change via the ViewModel

    <i:Interaction.Triggers>
        <ei:DataTrigger Binding="{Binding ConfirmedAnswerStatus}" Value="Unanswered">
            <ei:GoToStateAction StateName="UnansweredState" UseTransitions="False" />
        </ei:DataTrigger>
        <ei:DataTrigger Binding="{Binding ConfirmedAnswerStatus}" Value="Correct">
            <ei:GoToStateAction StateName="CorrectlyAnsweredState" UseTransitions="True" />
        </ei:DataTrigger>
        <ei:DataTrigger Binding="{Binding ConfirmedAnswerStatus}" Value="Incorrect">
            <ei:GoToStateAction StateName="IncorrectlyAnsweredState" UseTransitions="True" />
        </ei:DataTrigger>
    </i:Interaction.Triggers>

Answer 3

SL中有一个可以移植到WPF的DataStateSwitchBehavior：Anyone have a DataStateSwitchBehavior for WPF4?

语法非常简单：

 <is:DataStateSwitchBehavior Binding="{Binding Orientation}">
     <is:DataStateSwitchCase Value="Left" State="LeftState"/>
     <is:DataStateSwitchCase Value="Right" State="RightState"/>
     <is:DataStateSwitchCase Value="Down" State="DownState"/>
     <is:DataStateSwitchCase Value="Up" State="UpState"/>
 <is:DataStateSwitchCase/>

Enum的DataStateBehavior而不是bool？串？

3 个答案: