Question

我在名为“Error”的Style中创建了一个状态，并在故事板中附加了动画。

我希望能够在满足特定条件的情况下从使用该Style的Control启动该动画。

例如，当我的View的DataContext中的属性设置为某个值时。

我究竟如何启动控件样式中定义的故事板？

Answer 1

在控件后面的代码中执行

Storyboard myStoryboard = this.FindResource("NameOfMyStoryBoard") as Storyboard;

if(myStoryboard != null)
{
    myStoryboard.Begin();
}

如果您的故事板未设置为资源但嵌入在您的样式中，请将其声明为资源并以您的样式引用它。

MSDN文档：Storyboard

Answer 2

以下是使用触发器从XAML执行此操作的方法：

<Style TargetType="Button" x:Key="MyStyle">
            <Style.Resources>
                <Storyboard x:Key="MyGetFocusAnimation">
                    <DoubleAnimation Storyboard.TargetProperty="Height"
                                     To="50"
                                     Duration="0:0:.3" />
                </Storyboard>
                <Storyboard x:Key="MyLoseFocusAnimation">
                    <DoubleAnimation Storyboard.TargetProperty="Height"
                                     To="30"
                                     Duration="0:0:.3" />
                </Storyboard>
            </Style.Resources>
            <Style.Triggers>
                <Trigger Property="IsMouseOver"
                         Value="True">
                    <Trigger.EnterActions>
                        <BeginStoryboard Storyboard="{StaticResource MyGetFocusAnimation}" />
                    </Trigger.EnterActions>
                    <Trigger.ExitActions>
                        <BeginStoryboard Storyboard="{StaticResource MyLoseFocusAnimation}" />
                    </Trigger.ExitActions>
                </Trigger>
                <Trigger Property="IsKeyboardFocusWithin"
                         Value="True">
                    <Trigger.EnterActions>
                        <BeginStoryboard Storyboard="{StaticResource MyGetFocusAnimation}" />
                    </Trigger.EnterActions>
                    <Trigger.ExitActions>
                        <BeginStoryboard Storyboard="{StaticResource MyLoseFocusAnimation}" />
                    </Trigger.ExitActions>
                </Trigger>
            </Style.Triggers>
        </Style>

在定义上面的样式后，您只需告诉按钮使用哪种样式：

<Button Content="Content" Height="20" Width="100" Style="{StaticResource MyStyle}"/>

Answer 3

我最终创建了一个可以容纳我所有控件的课程。验证依赖属性：

public class ValidationProperties
{
     #region IsValid Dependency Property

    /// <summary>
    /// An attached dependency property which provides an
    /// </summary>
    public static readonly DependencyProperty IsValidProperty;

    /// <summary>
    /// Gets the <see cref="IsValidProperty"/> for a given
    /// <see cref="DependencyObject"/>, which provides an
    /// </summary>
    public static bool GetIsValid(DependencyObject obj)
    {
        return (bool)obj.GetValue(IsValidProperty);
    }

    /// <summary>
    /// Sets the attached <see cref="IsValidProperty"/> for a given
    /// <see cref="DependencyObject"/>, which provides an
    /// </summary>
    public static void SetIsValid(DependencyObject obj, bool value)
    {
        obj.SetValue(IsValidProperty, value);
    }

     #endregion IsValid Dependency Property

    static ValidationProperties()
    {
        // Register attached dependency property
        IsValidProperty = DependencyProperty.RegisterAttached("IsValid",
                                                            typeof(bool),
                                                            typeof(ValidationProperties), 
                                                            new FrameworkPropertyMetadata(true));
    }
}

在此之后，我修改了样式以启动动画，具体取决于使用该样式的控件的属性值：

(...)

<Trigger Property="AttachedProperties:ValidationProperties.IsValid" Value="false">
    <Trigger.EnterActions>
        <BeginStoryboard Storyboard="{StaticResource ControlIsInvalid}"/>
    </Trigger.EnterActions>
</Trigger>

(...)

我最终将Control上的Dependency属性绑定到模型中的值（通过View-Model）：

<TextBox x:Name="UsernameTextbox"
       (...)
       AttachedProperties:ValidationProperties.IsValid="{Binding SessionHandler.SessionUser.UsernameIsValid}"/>

如何从实现它的Control中启动Style中定义的动画？

3 个答案: