我在 MainWindow 的 LayoutRoot Grid 中定义了两个视觉状态,如下所示:
<Grid x:Name="LayoutRoot" Background="#FF434343" ShowGridLines="True">
<Grid.RowDefinitions>
<RowDefinition Height="100"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<VisualStateManager.CustomVisualStateManager>
<ic:ExtendedVisualStateManager/>
</VisualStateManager.CustomVisualStateManager>
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="VisualStateLogin">
<VisualStateGroup.Transitions>
<VisualTransition GeneratedDuration="00:00:00.6000000"/>
</VisualStateGroup.Transitions>
<VisualState x:Name="LoggedOn">
<Storyboard>
<ObjectAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000" Storyboard.TargetName="{x:Null}" Storyboard.TargetProperty="(Window.WindowStyle)">
<DiscreteObjectKeyFrame KeyTime="00:00:00" Value="{x:Static WindowStyle.None}"/>
</ObjectAnimationUsingKeyFrames>
<BooleanAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000" Storyboard.TargetName="{x:Null}" Storyboard.TargetProperty="(Window.AllowsTransparency)">
<DiscreteBooleanKeyFrame KeyTime="00:00:00" Value="True"/>
</BooleanAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
<VisualState x:Name="LoggedOff">
<Storyboard>
<DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000" Storyboard.TargetName="brdContent" Storyboard.TargetProperty="(UIElement.Opacity)">
<SplineDoubleKeyFrame KeyTime="00:00:00" Value="0.1"/>
</DoubleAnimationUsingKeyFrames>
<BooleanAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000" Storyboard.TargetName="brdContent" Storyboard.TargetProperty="(UIElement.IsEnabled)">
<DiscreteBooleanKeyFrame KeyTime="00:00:00" Value="False"/>
</BooleanAnimationUsingKeyFrames>
<BooleanAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000" Storyboard.TargetName="ucTabButtons" Storyboard.TargetProperty="(UIElement.IsEnabled)">
<DiscreteBooleanKeyFrame KeyTime="00:00:00" Value="False"/>
</BooleanAnimationUsingKeyFrames>
<DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000" Storyboard.TargetName="ucTabButtons" Storyboard.TargetProperty="(UIElement.Opacity)">
<SplineDoubleKeyFrame KeyTime="00:00:00" Value="0.4"/>
</DoubleAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
考虑到 MainWindow 代码隐藏,它可以很好地从一种状态切换到另一种状态,如下所示:
void MainWindow_Loaded(object sender, RoutedEventArgs e)
{
//ExtendedVisualStateManager.GoToElementState(this.LayoutRoot as FrameworkElement, "LoggedOff", false);
}
但是现在,我需要能够从 MainWindow 内的用户控件切换状态......
我试过了:
private void btnOk_Click(object sender, System.Windows.RoutedEventArgs e)
{
MainWindow parent = new MainWindow();
Grid root = new Grid();
root = (Grid)parent.FindName("LayoutRoot");
ExtendedVisualStateManager.GoToElementState(root as FrameworkElement, "LoggedOn", true);
}
它给了我以下例外:
System.NullReferenceException 未处理 Message="对象引用未设置为对象的实例。" 来源="WPFToolkit"
有人知道如何从用户控件切换状态吗?
谢谢你,
乔西