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Wpf樣式和附加屬性

[英]Wpf styles and attached properties

我一直在玩行為,我遇到了一個有趣的問題。 這是我的行為:

public class AddNewBehavior : BaseBehavior<RadGridView, AddNewBehavior>
{
    public static readonly DependencyProperty IsEnabledProperty = DependencyProperty.RegisterAttached("IsEnabled", typeof(bool), typeof(AddNewBehavior), new FrameworkPropertyMetadata(false, OnIsEnabledChanged));

    public static void SetIsEnabled(DependencyObject obj, bool isEnabled)
    {
        obj.SetValue(IsEnabledProperty, isEnabled);
    }

    public static bool GetIsEnabled(DependencyObject obj)
    {
        return (bool)obj.GetValue(IsEnabledProperty);
    } ... OnIsEnabledChanged(...)}

當我設置這樣的樣式時,這將很有用:

<Style TargetType="telerikGridView:RadGridView">
    <Setter Property="Behaviors:AddNewBehavior.IsEnabled" Value="true" />
</Style>

但是,如果我把它放在抽象類中

public abstract class BaseBehavior<TObj, TBehavior> : Behavior<TObj> 
    where TObj : DependencyObject
    where TBehavior : BaseBehavior<TObj, TBehavior>, new()
{
    public static readonly DependencyProperty IsEnabledProperty = DependencyProperty.RegisterAttached("IsEnabled", typeof(bool), typeof(TBehavior), new FrameworkPropertyMetadata(false, OnIsEnabledChanged));

    public static void SetIsEnabled(DependencyObject obj, bool isEnabled)
    {
        obj.SetValue(IsEnabledProperty, isEnabled);
    }

    public static bool GetIsEnabled(DependencyObject obj)
    {
        return (bool)obj.GetValue(IsEnabledProperty);
    }

    public static void OnIsEnabledChanged(DependencyObject dpo, DependencyPropertyChangedEventArgs e)
    {
        BehaviorCollection behaviorCollection = Interaction.GetBehaviors(dpo);

        if ((bool)e.NewValue)
        {
            var firstOrDefault = behaviorCollection.Where(b => b.GetType() == typeof(TBehavior)).FirstOrDefault();

            if (firstOrDefault == null)
            {
                behaviorCollection.Add(new TBehavior());
            }
        }
    }
}

樣式聲明將粉碎為“值不能為空。屬性名稱:屬性”。

不知道我做錯了什么,在基類中使用IsEnabled代碼會很棒。

謝謝,

在基類的IsEnabledProperty定義中,嘗試將其更改為:

public static readonly DependencyProperty IsEnabledProperty = 
  DependencyProperty.RegisterAttached(
    "IsEnabled", 
    typeof(bool), 
    typeof(BaseBehavior<TObj, TBehavior>), 
    new FrameworkPropertyMetadata(false, OnIsEnabledChanged)
  );

也就是說,不是將TBehavior作為DP OwnerType傳遞, BaseBehavior<TObj, TBehavior>傳入BaseBehavior<TObj, TBehavior>

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