设置一个属性与一个EventTrigger

Question

我想要能够设定的属性与一个EventTrigger，有一些问题与这一点。

1)EventTriggers仅支持的行动，所以我必须用一个故事情节向我的特性。

2)有一次我使用一个故事情节，我有两个选择：

• 停止：一旦动画已经停止的价值恢复到前的动画开始
• HoldEnd:这个锁酒店，所以，无论是代码，也没有用户相互作用可以改变的财产，动画是保持。

在下面的例子，我想要设置IsChecked财产假时的点击按钮我想让用户能够改变IsChecked和/或我希望能够改变的酒店代码。

例如：

<EventTrigger
    SourceName="myButton"
    RoutedEvent="Button.Click">
    <EventTrigger.Actions>
        <BeginStoryboard>
            <Storyboard>
                <BooleanAnimationUsingKeyFrames
                    Storyboard.TargetName="myCheckBox"
                    Storyboard.TargetProperty="IsChecked"
                    FillBehavior="Stop">
                    <DiscreteBooleanKeyFrame
                        KeyTime="00:00:00"
                        Value="False" />
                </BooleanAnimationUsingKeyFrames>
            </Storyboard>
        </BeginStoryboard>
    </EventTrigger.Actions>
</EventTrigger>

我意识到我可以使用的"完成"事件后的故事情节完成设置价值为假。然而，在这种情况下我想包含的逻辑内的转换，因为这种逻辑将使用以上定义的控制，也只有特定的用户界面。

Answer 1

因为我喜欢换，对这种任务，我切换到码后面。 附加行为 是一个良好的模式。请记住，表达混3 提供了一个标准的方式 程序和使用的行为。还有 一些现有的人 上表达的社会网站。

Answer 2

只是创建你自己的行动。

namespace WpfUtil
{
    using System.Reflection;
    using System.Windows;
    using System.Windows.Interactivity;


    /// <summary>
    /// Sets the designated property to the supplied value. TargetObject
    /// optionally designates the object on which to set the property. If
    /// TargetObject is not supplied then the property is set on the object
    /// to which the trigger is attached.
    /// </summary>
    public class SetPropertyAction : TriggerAction<FrameworkElement>
    {
        // PropertyName DependencyProperty.

        /// <summary>
        /// The property to be executed in response to the trigger.
        /// </summary>
        public string PropertyName
        {
            get { return (string)GetValue(PropertyNameProperty); }
            set { SetValue(PropertyNameProperty, value); }
        }

        public static readonly DependencyProperty PropertyNameProperty
            = DependencyProperty.Register("PropertyName", typeof(string),
            typeof(SetPropertyAction));


        // PropertyValue DependencyProperty.

        /// <summary>
        /// The value to set the property to.
        /// </summary>
        public object PropertyValue
        {
            get { return GetValue(PropertyValueProperty); }
            set { SetValue(PropertyValueProperty, value); }
        }

        public static readonly DependencyProperty PropertyValueProperty
            = DependencyProperty.Register("PropertyValue", typeof(object),
            typeof(SetPropertyAction));


        // TargetObject DependencyProperty.

        /// <summary>
        /// Specifies the object upon which to set the property.
        /// </summary>
        public object TargetObject
        {
            get { return GetValue(TargetObjectProperty); }
            set { SetValue(TargetObjectProperty, value); }
        }

        public static readonly DependencyProperty TargetObjectProperty
            = DependencyProperty.Register("TargetObject", typeof(object),
            typeof(SetPropertyAction));


        // Private Implementation.

        protected override void Invoke(object parameter)
        {
            object target = TargetObject ?? AssociatedObject;
            PropertyInfo propertyInfo = target.GetType().GetProperty(
                PropertyName,
                BindingFlags.Instance|BindingFlags.Public
                |BindingFlags.NonPublic|BindingFlags.InvokeMethod);

            propertyInfo.SetValue(target, PropertyValue);
        }
    }
}

在这种情况下，我结合的财产称为未关闭在我的视图模型.

<Grid>

    <Button>
        <i:Interaction.Triggers>
            <i:EventTrigger EventName="Click">
                <wpf:SetPropertyAction PropertyName="DialogResult" TargetObject="{Binding}"
                                       PropertyValue="{x:Static mvvm:DialogResult.Cancel}"/>
            </i:EventTrigger>
        </i:Interaction.Triggers>
        Cancel
    </Button>

</Grid>

Answer 3

我修改的中微子的溶液使xaml看起来不那么详细时指定的价值：

对不起，没有图片呈现换，只是想象一个[=]汉堡按钮，你击和它变成[<-]后按钮，也可切换的可见度的网格。

xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"

...

<Grid>
    <Button x:Name="optionsButton">
        <i:Interaction.Triggers>
            <i:EventTrigger EventName="Click">
                <local:SetterAction PropertyName="Visibility" Value="Collapsed" />
                <local:SetterAction PropertyName="Visibility" TargetObject="{Binding ElementName=optionsBackButton}" Value="Visible" />
                <local:SetterAction PropertyName="Visibility" TargetObject="{Binding ElementName=optionsPanel}" Value="Visible" />
            </i:EventTrigger>
        </i:Interaction.Triggers>

        <glyphs:Hamburger Width="10" Height="10" />
    </Button>

    <Button x:Name="optionsBackButton" Visibility="Collapsed">
        <i:Interaction.Triggers>
            <i:EventTrigger EventName="Click">
                <local:SetterAction PropertyName="Visibility" Value="Collapsed" />
                <local:SetterAction PropertyName="Visibility" TargetObject="{Binding ElementName=optionsButton}" Value="Visible" />
                <local:SetterAction PropertyName="Visibility" TargetObject="{Binding ElementName=optionsPanel}" Value="Collapsed" />
            </i:EventTrigger>
        </i:Interaction.Triggers>

        <glyphs:Back Width="12" Height="11" />
    </Button>
</Grid>

...

<Grid Grid.RowSpan="2" x:Name="optionsPanel" Visibility="Collapsed">

</Grid>

你也可以指定价值，这样在中微子的解决方案：

<Button x:Name="optionsButton">
    <i:Interaction.Triggers>
        <i:EventTrigger EventName="Click">
            <local:SetterAction PropertyName="Visibility" Value="{x:Static Visibility.Collapsed}" />
            <local:SetterAction PropertyName="Visibility" TargetObject="{Binding ElementName=optionsBackButton}" Value="{x:Static Visibility.Visible}" />
            <local:SetterAction PropertyName="Visibility" TargetObject="{Binding ElementName=optionsPanel}" Value="{x:Static Visibility.Visible}" />
        </i:EventTrigger>
    </i:Interaction.Triggers>

    <glyphs:Hamburger Width="10" Height="10" />
</Button>

和这里的代码。

using System;
using System.ComponentModel;
using System.Reflection;
using System.Windows;
using System.Windows.Interactivity;

namespace Mvvm.Actions
{
    /// <summary>
    /// Sets a specified property to a value when invoked.
    /// </summary>
    public class SetterAction : TargetedTriggerAction<FrameworkElement>
    {
        #region Properties

        #region PropertyName

        /// <summary>
        /// Property that is being set by this setter.
        /// </summary>
        public string PropertyName
        {
            get { return (string)GetValue(PropertyNameProperty); }
            set { SetValue(PropertyNameProperty, value); }
        }

        public static readonly DependencyProperty PropertyNameProperty =
            DependencyProperty.Register("PropertyName", typeof(string), typeof(SetterAction),
            new PropertyMetadata(String.Empty));

        #endregion

        #region Value

        /// <summary>
        /// Property value that is being set by this setter.
        /// </summary>
        public object Value
        {
            get { return (object)GetValue(ValueProperty); }
            set { SetValue(ValueProperty, value); }
        }

        public static readonly DependencyProperty ValueProperty =
            DependencyProperty.Register("Value", typeof(object), typeof(SetterAction),
            new PropertyMetadata(null));

        #endregion

        #endregion

        #region Overrides

        protected override void Invoke(object parameter)
        {
            var target = TargetObject ?? AssociatedObject;

            var targetType = target.GetType();

            var property = targetType.GetProperty(PropertyName, BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Static | BindingFlags.Instance);
            if (property == null)
                throw new ArgumentException(String.Format("Property not found: {0}", PropertyName));

            if (property.CanWrite == false)
                throw new ArgumentException(String.Format("Property is not settable: {0}", PropertyName));

            object convertedValue;

            if (Value == null)
                convertedValue = null;

            else
            {
                var valueType = Value.GetType();
                var propertyType = property.PropertyType;

                if (valueType == propertyType)
                    convertedValue = Value;

                else
                {
                    var propertyConverter = TypeDescriptor.GetConverter(propertyType);

                    if (propertyConverter.CanConvertFrom(valueType))
                        convertedValue = propertyConverter.ConvertFrom(Value);

                    else if (valueType.IsSubclassOf(propertyType))
                        convertedValue = Value;

                    else
                        throw new ArgumentException(String.Format("Cannot convert type '{0}' to '{1}'.", valueType, propertyType));
                }
            }

            property.SetValue(target, convertedValue);
        }

        #endregion
    }
}

Answer 4

停止故事情节，可以在码后面，或者换，根据需要来源。

如果EventTrigger移动以外的按钮，那么我们可以继续前进，目标与另一个EventTrigger会告诉故事情节，以停止。当故事情节是停止以这种方式也不会恢复到以前的价值。

在这里，我已经移动按钮。点击EventTrigger到周围在这种情况下，和加入一个新的EventTrigger上的选项。点击停止按钮的故事情节的时候框被点击。这让我们检查，并取消框当它被点击以及为我们提供了所需的取消行为的按钮。

    <StackPanel x:Name="myStackPanel">

        <CheckBox x:Name="myCheckBox"
                  Content="My CheckBox" />

        <Button Content="Click to Uncheck"
                x:Name="myUncheckButton" />

        <Button Content="Click to check the box in code."
                Click="OnClick" />

        <StackPanel.Triggers>

            <EventTrigger RoutedEvent="Button.Click"
                          SourceName="myUncheckButton">
                <EventTrigger.Actions>
                    <BeginStoryboard x:Name="myBeginStoryboard">
                        <Storyboard x:Name="myStoryboard">
                            <BooleanAnimationUsingKeyFrames Storyboard.TargetName="myCheckBox"
                                                            Storyboard.TargetProperty="IsChecked">
                                <DiscreteBooleanKeyFrame KeyTime="00:00:00"
                                                         Value="False" />
                            </BooleanAnimationUsingKeyFrames>
                        </Storyboard>
                    </BeginStoryboard>
                </EventTrigger.Actions>
            </EventTrigger>

            <EventTrigger RoutedEvent="CheckBox.Click"
                          SourceName="myCheckBox">
                <EventTrigger.Actions>
                    <StopStoryboard BeginStoryboardName="myBeginStoryboard" />
                </EventTrigger.Actions>
            </EventTrigger>

        </StackPanel.Triggers>
    </StackPanel>

停止故事情节的代码，我们将不得不做一些轻微不同。第三个按钮提供的方法，我们将停止故事情节和设置IsChecked酒店，回到真实的，通过代码。

我们不能叫myStoryboard.Stop()因为我们没开始的故事情节通过代码设置isControllable参数。相反，我们可以删除的故事情节。要做到这一点，我们需要的。这故事情节上存在，在这种情况下，我们在这种情况下.一旦故事情节是删除，我们可以再次组的IsChecked财产与它持续存在的用户界面。

    private void OnClick(object sender, RoutedEventArgs e)
    {
        myStoryboard.Remove(myStackPanel);
        myCheckBox.IsChecked = true;
    }