如何从XAML访问元素资源中的故事板?

时间:2013-04-06 07:46:31

标签: c# wpf xaml binding storyboard

考虑以下代码:

<UserControl x:Class="MyApp.MyControl"
             ...
         xmlns:local="clr-namespace:MyApp"
         DataContext="{Binding RelativeSource={RelativeSource Mode=Self}}">

    <UserControl.Template>
        <ControlTemplate>
            <ControlTemplate.Resources>
                <Storyboard x:Key="MyStory">
                    <ColorAnimationUsingKeyFrames Storyboard.TargetProperty="(Border.BorderBrush).(SolidColorBrush.Color)" Storyboard.TargetName="brdBase">
                        <SplineColorKeyFrame KeyTime="0:0:1" Value="Red"/>
                    </ColorAnimationUsingKeyFrames>
                </Storyboard>
            </ControlTemplate.Resources>

            <Border x:Name="brdBase" BorderThickness="1" BorderBrush="Cyan" Background="Black">
                ...
            </Border>

            <ControlTemplate.Triggers>
                <Trigger SourceName="brdBase" Property="IsMouseOver" Value="True">
                    <Trigger.EnterActions>
                        <BeginStoryboard Storyboard="{StaticResource MyStory}"/>
                    </Trigger.EnterActions>
                </Trigger>
            </ControlTemplate.Triggers>
        </ControlTemplate>
    </UserControl.Template>
</UserControl>

上面的代码没有问题。现在,我想将MyStory的关键帧值绑定到此用户控件的DP(名为SpecialColor),如下所示:

<Storyboard x:Key="MyStory">
    <ColorAnimationUsingKeyFrames Storyboard.TargetProperty="(Border.BorderBrush).(SolidColorBrush.Color)" Storyboard.TargetName="brdBase">
        <SplineColorKeyFrame KeyTime="0:0:1" Value="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type local:MyControl}}, Path=SpecialColor}"/>
    </ColorAnimationUsingKeyFrames>
</Storyboard>

出错:

无法冻结此Storyboard时间轴树以供跨线程使用。

使用后面的代码可以做到这一点。但是我怎么能只用XAML呢?


代码隐藏辅助解决方案:

第1步:MyStory故事板放入brdBase资源。

<UserControl.Template>
    <ControlTemplate>
        <Border x:Name="brdBase" BorderThickness="1" BorderBrush="Cyan" Background="Black">
            <Border.Resources>
                <Storyboard x:Key="MyStory">
                    <ColorAnimationUsingKeyFrames Storyboard.TargetProperty="(Border.BorderBrush).(SolidColorBrush.Color)" Storyboard.TargetName="brdBase">
                        <SplineColorKeyFrame KeyTime="0:0:1" Value="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type local:MyControl}}, Path=SpecialColor}"/>
                    </ColorAnimationUsingKeyFrames>
                </Storyboard>
            </Border.Resources>
            ...
        </Border>

        <ControlTemplate.Triggers>
            <Trigger SourceName="brdBase" Property="IsMouseOver" Value="True">
                <Trigger.EnterActions>
                    <BeginStoryboard Storyboard="{StaticResource MyStory}"/>
                </Trigger.EnterActions>
            </Trigger>
        </ControlTemplate.Triggers>
    </ControlTemplate>
</UserControl.Template>

错误: 无法找到名为“MyStory”的资源。资源名称区分大小写。

第2步:取消Trigger属性上的IsMouseOver并从后面的代码中开始MyStory

<UserControl.Template>
    <ControlTemplate>
        <Border x:Name="brdBase" BorderThickness="1" BorderBrush="Cyan" Background="Black" MouseEnter="brdBase_MouseEnter">
            <Border.Resources>
                <Storyboard x:Key="MyStory">
                    <ColorAnimationUsingKeyFrames Storyboard.TargetProperty="(Border.BorderBrush).(SolidColorBrush.Color)" Storyboard.TargetName="brdBase">
                        <SplineColorKeyFrame KeyTime="0:0:1" Value="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type local:MyControl}}, Path=SpecialColor}"/>
                    </ColorAnimationUsingKeyFrames>
                </Storyboard>
            </Border.Resources>
        </Border>
    </ControlTemplate>
</UserControl.Template>

C#Code-Behind:

private void brdBase_MouseEnter(object sender, MouseEventArgs e)
{
   Border grdRoot = (Border)this.Template.FindName("brdBase", this);
   Storyboard story = grdRoot.Resources["MyStory"] as Storyboard;

   story.Begin(this, this.Template);
}

第3步:解决方案已经完成,但第一次无效。幸运的是,这个问题有一个解决方法。将ControlTemplate放在Style

就足够了

(我需要其他Trigger种类型而不是EventTrigger,并且必须使用UserControl包装ControlTemplate个元素。)


更新

关于使用ObjectDataProvider的想法失败了。

  1. ObjectDataProvider 资源不能用于提供故事板!错误报告是:
    • XamlParseException:设置属性'System.Windows.Media.Animation.BeginStoryboard.Storyboard'引发异常。
    • InnerException:'System.Windows.Data.ObjectDataProvider'不是属性'Storyboard'的有效值。
  2. AssociatedControl DP始终为空。
  3. 以下是代码:

    <UserControl.Template>
        <ControlTemplate>
            <ControlTemplate.Resources>
                <local:StoryboardFinder x:Key="StoryboardFinder1" AssociatedControl="{Binding ElementName=brdBase}"/>
                <ObjectDataProvider x:Key="dataProvider" ObjectInstance="{StaticResource StoryboardFinder1}" MethodName="Finder">
                    <ObjectDataProvider.MethodParameters>
                        <sys:String>MyStory</sys:String>
                    </ObjectDataProvider.MethodParameters>
                </ObjectDataProvider>
            </ControlTemplate.Resources>
    
            <Border x:Name="brdBase" BorderThickness="1" BorderBrush="Cyan" Background="Black">
                <Border.Resources>
                    <Storyboard x:Key="MyStory">
                        <ColorAnimationUsingKeyFrames Storyboard.TargetProperty="(Border.BorderBrush).(SolidColorBrush.Color)" Storyboard.TargetName="brdBase">
                            <SplineColorKeyFrame KeyTime="0:0:1" Value="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type local:MyControl}}, Path=SpecialColor}"/>
                        </ColorAnimationUsingKeyFrames>
                    </Storyboard>
                </Border.Resources>
                ...
            </Border>
    
            <ControlTemplate.Triggers>
                <Trigger SourceName="brdBase" Property="IsMouseOver" Value="True">
                    <Trigger.EnterActions>
                        <BeginStoryboard Storyboard="{StaticResource dataProvider}"/>
                    </Trigger.EnterActions>
                </Trigger>
            </ControlTemplate.Triggers>
        </ControlTemplate>
    </UserControl.Template>
    

    StoryboardFinder类:

    public class StoryboardFinder : DependencyObject
    {
        #region ________________________________________  AssociatedControl
    
        public Control AssociatedControl
        {
            get { return (Control)GetValue(AssociatedControlProperty); }
            set { SetValue(AssociatedControlProperty, value); }
        }
    
        public static readonly DependencyProperty AssociatedControlProperty =
            DependencyProperty.Register("AssociatedControl",
                                        typeof(Control),
                                        typeof(StoryboardFinder),
                                        new FrameworkPropertyMetadata(null, FrameworkPropertyMetadataOptions.None));
    
        #endregion
    
        public Storyboard Finder(string resourceName)
        {
            //
            // Associated control is always null :(
            //
            return new Storyboard();
        }
    }
    

2 个答案:

答案 0 :(得分:3)

嗯,你不能真正绑定到“To”和From,因为故事板必须被冻结,以便有效地使用跨线程。

解决方案1)最简单的解决方案,无需攻击(涉及代码隐藏): 添加MouseOver事件处理程序&amp;在事件处理程序中,找到必要的动画,直接设置“To”属性,这样就不会使用绑定,可以完成“冻结”。这样你就不会对任何东西进行硬编码:)。

解决方案2)有一个很酷的黑客只支持XAML(有点转换魔法),但我不建议。尽管如此,它很酷:) WPF animation: binding to the "To" attribute of storyboard animation见杰森的回答。

您可以尝试更多的事情:

解决方案3)不要使用依赖属性,而是实现INotifyProperthChanged。这样你仍然可以“绑定”。请注意,我认为这在理论上应该可行,但我还没有尝试过。

解决方案4)对您的绑定应用Mode = OneTime。也许它有效?

解决方案5)编写您自己的附加行为,该行为将评估正确线程上的依赖项属性并设置“To”属性。我认为这将是一个很好的解决方案。

这也是很好的重复:WPF Animation "Cannot freeze this Storyboard timeline tree for use across threads"

答案 1 :(得分:3)

如果此代码为真,该怎么办?

<UserControl x:Class="MyApp.MyControl"
             ...
             xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
             xmlns:l="clr-namespace:MyApp"
             DataContext="{Binding RelativeSource={RelativeSource Mode=Self}}">

    <UserControl.Resources>
        <Style TargetType="{x:Type l:MyControl}">
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type l:MyControl}">
                        <Border x:Name="brdBase" BorderThickness="1" BorderBrush="Cyan" Background="Black">
                            <Border.Resources>
                                <Storyboard x:Key="MyStory">
                                    <ColorAnimationUsingKeyFrames Storyboard.TargetProperty="(Border.BorderBrush).(SolidColorBrush.Color)" Storyboard.TargetName="brdBase">
                                        <SplineColorKeyFrame KeyTime="0:0:1" Value="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type l:MyControl}}, Path=SpecialColor}"/>
                                    </ColorAnimationUsingKeyFrames>
                                </Storyboard>
                            </Border.Resources>

                            <i:Interaction.Triggers>
                                <l:InteractiveTrigger Property="IsMouseOver" Value="True">
                                    <l:InteractiveTrigger.CommonActions>
                                        <BeginStoryboard Storyboard="{StaticResource MyStory}"/>
                                    </l:InteractiveTrigger.CommonActions>
                                </l:InteractiveTrigger>
                            </i:Interaction.Triggers>
                        </Border>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </UserControl.Resources>
</UserControl>

如果是这样,我可以在IsMouseOver属性上触发...

我很高兴地说这是一个有效的代码:)我只能在EventTrigger标记中使用<Border.Triggers>。这是限制。所以我开始考虑这个想法:如果我有一个可以在FrameworkElement.Triggers范围内工作的自定义触发器怎么办?这是代码:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Windows;
using System.Windows.Interactivity;
using System.Windows.Media.Animation;

namespace TriggerTest
{
    /// <summary>
    /// InteractiveTrigger is a trigger that can be used as the System.Windows.Trigger but in the System.Windows.Interactivity.
    /// <para>
    /// Note: There is neither `EnterActions` nor `ExitActions` in this class. The `CommonActions` can be used instead of `EnterActions`.
    /// Also, the `Actions` property which is of type System.Windows.Interactivity.TriggerAction can be used.
    /// </para>
    /// <para> </para>
    /// <para>
    /// There is only one kind of triggers (i.e. EventTrigger) in the System.Windows.Interactivity. So you can use the following triggers in this namespace:
    /// <para>1- InteractiveTrigger : Trigger</para>
    /// <para>2- InteractiveMultiTrigger : MultiTrigger</para>
    /// <para>3- InteractiveDataTrigger : DataTrigger</para>
    /// <para>4- InteractiveMultiDataTrigger : MultiDataTrigger</para>
    /// </para>
    /// </summary>
    public class InteractiveTrigger : TriggerBase<FrameworkElement>
    {
        #region ___________________________________________________________________________________  Properties

        #region ________________________________________  Value

        /// <summary>
        /// [Wrapper property for ValueProperty]
        /// <para>
        /// Gets or sets the value to be compared with the property value of the element. The comparison is a reference equality check.
        /// </para>
        /// </summary>
        public object Value
        {
            get { return (object)GetValue(ValueProperty); }
            set { SetValue(ValueProperty, value); }
        }

        public static readonly DependencyProperty ValueProperty =
            DependencyProperty.Register("Value",
                                        typeof(object),
                                        typeof(InteractiveTrigger),
                                        new FrameworkPropertyMetadata(null, FrameworkPropertyMetadataOptions.None, OnValuePropertyChanged));

        private static void OnValuePropertyChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
        {
            InteractiveTrigger instance = sender as InteractiveTrigger;

            if (instance != null)
            {
                if (instance.CanFire)
                    instance.Fire();
            }
        }

        #endregion


        /// <summary>
        /// Gets or sets the name of the object with the property that causes the associated setters to be applied.
        /// </summary>
        public string SourceName
        {
            get;
            set;
        }

        /// <summary>
        /// Gets or sets the property that returns the value that is compared with this trigger.Value property. The comparison is a reference equality check.
        /// </summary>
        public DependencyProperty Property
        {
            get;
            set;
        }

        /// <summary>
        /// Gets or sets a collection of System.Windows.Setter objects, which describe the property values to apply when the trigger object becomes active.
        /// </summary>
        public List<Setter> Setters
        {
            get;
            set;
        }

        /// <summary>
        /// Gets or sets the collection of System.Windows.TriggerAction objects to apply when this trigger object becomes active.
        /// </summary>
        public List<System.Windows.TriggerAction> CommonActions
        {
            get;
            set;
        }

        /// <summary>
        /// Gets a value indicating whether this trigger can be active to apply setters and actions.
        /// </summary>
        private bool CanFire
        {
            get
            {
                if (this.AssociatedObject == null)
                {
                    return false;
                }
                else
                {
                    object associatedValue;

                    if (string.IsNullOrEmpty(SourceName))
                        associatedValue = this.AssociatedObject.GetValue(Property);
                    else
                        associatedValue = (this.AssociatedObject.FindName(SourceName) as DependencyObject).GetValue(Property);

                    TypeConverter typeConverter = TypeDescriptor.GetConverter(Property.PropertyType);
                    object realValue = typeConverter.ConvertFromString(Value.ToString());

                    return associatedValue.Equals(realValue);
                }
            }
        }

        #endregion


        #region ___________________________________________________________________________________  Methods

        /// <summary>
        /// Fires (activates) current trigger by setting setter values and invoking all actions.
        /// </summary>
        private void Fire()
        {
            //
            // Setting setters values to their associated properties..
            //
            foreach (Setter setter in Setters)
            {
                if (string.IsNullOrEmpty(setter.TargetName))
                    this.AssociatedObject.SetValue(setter.Property, setter.Value);
                else
                    (this.AssociatedObject.FindName(setter.TargetName) as DependencyObject).SetValue(setter.Property, setter.Value);
            }

            //
            // Firing actions.. 
            //
            foreach (System.Windows.TriggerAction action in CommonActions)
            {
                Type actionType = action.GetType();

                if (actionType == typeof(BeginStoryboard))
                {
                    (action as BeginStoryboard).Storyboard.Begin();
                }
                else
                    throw new NotImplementedException();
            }

            this.InvokeActions(null);
        }

        #endregion


        #region ___________________________________________________________________________________  Events

        public InteractiveTrigger()
        {
            Setters = new List<Setter>();
            CommonActions = new List<System.Windows.TriggerAction>();
        }

        protected override void OnAttached()
        {
            base.OnAttached();

            if (Property != null)
            {
                object propertyAssociatedObject;

                if (string.IsNullOrEmpty(SourceName))
                    propertyAssociatedObject = this.AssociatedObject;
                else
                    propertyAssociatedObject = this.AssociatedObject.FindName(SourceName);

                //
                // Adding a property changed listener to the property associated-object..
                //
                DependencyPropertyDescriptor dpDescriptor = DependencyPropertyDescriptor.FromProperty(Property, propertyAssociatedObject.GetType());
                dpDescriptor.AddValueChanged(propertyAssociatedObject, PropertyListener_ValueChanged);
            }
        }

        protected override void OnDetaching()
        {
            base.OnDetaching();

            if (Property != null)
            {
                object propertyAssociatedObject;

                if (string.IsNullOrEmpty(SourceName))
                    propertyAssociatedObject = this.AssociatedObject;
                else
                    propertyAssociatedObject = this.AssociatedObject.FindName(SourceName);

                //
                // Removing previously added property changed listener from the associated-object..
                //
                DependencyPropertyDescriptor dpDescriptor = DependencyPropertyDescriptor.FromProperty(Property, propertyAssociatedObject.GetType());
                dpDescriptor.RemoveValueChanged(propertyAssociatedObject, PropertyListener_ValueChanged);
            }
        }

        private void PropertyListener_ValueChanged(object sender, EventArgs e)
        {
            if (CanFire)
                Fire();
        }

        #endregion
    }
}

我还创建了其他触发器类型(即InteractiveMultiTriggerInteractiveDataTriggerInteractiveMultiDataTrigger)以及更多可以使条件和多条件EventTriggers成为可能的操作。如果专业人士确认这个解决方案,我会发布所有内容。

感谢您的关注!