首先，我有一个MVVM应用程序，其主WPF窗口包含许多嵌入和嵌套的网格。
在这些网格之一中，我放置了一个用户控件来重叠整个网格内容，如下所示：
查看（WPF主窗口）：
<controls:UCBusy Grid.Row="1" Grid.RowSpan="12"
Grid.ColumnSpan="3"
Visibility="{Binding Path=WaitMessageVisibility}"
Width="auto" Height="auto"/>
在视图模型中，我定义了属性绑定：
private Visibility _waitMessageVisibility = Visibility.Visible;
public Visibility WaitMessageVisibility
{
get
{
return _waitMessageVisibility;
}
set
{
if (_waitMessageVisibility == value) return;
_waitMessageVisibility = value;
OnPropertyChanged("WaitMessageVisibility");
}
}
如您所见，默认情况下，可见性设置为“可见”。
因此，我的用户控件（在右侧带有消息文本的纺锤）应该是可见的，而不是可见的。我究竟做错了什么？为了使用户控件可见，我使用ControlTemplate触发器将用户控件可见时，将Panel.ZIndex设置为较高的值（100）。见下文。
用户控制：
<UserControl x:Class="My.Apps.WPF.Demo.Controls.UCBusy"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Height="300" Width="300">
<UserControl.Resources>
<Color x:Key="FilledColor" A="255" B="222" R="176" G="196"/>
<Color x:Key="UnfilledColor" A="0" B="222" R="176" G="196"/>
<Style x:Key="BusyAnimationStyle" TargetType="Control">
<Setter Property="Background" Value="white" />
<Setter Property="Visibility" Value="Collapsed"/>
<Setter Property="Panel.ZIndex" Value="0" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="Control">
<ControlTemplate.Resources>
<Storyboard x:Key="Animation0" BeginTime="00:00:00.0" RepeatBehavior="Forever">
<ColorAnimationUsingKeyFrames Storyboard.TargetName="ellipse0" Storyboard.TargetProperty="(Shape.Fill).(SolidColorBrush.Color)">
<SplineColorKeyFrame KeyTime="00:00:00.0" Value="{StaticResource FilledColor}"/>
<SplineColorKeyFrame KeyTime="00:00:01.6" Value="{StaticResource UnfilledColor}"/>
</ColorAnimationUsingKeyFrames>
</Storyboard>
<Storyboard x:Key="Animation1" BeginTime="00:00:00.2" RepeatBehavior="Forever">
<ColorAnimationUsingKeyFrames Storyboard.TargetName="ellipse1" Storyboard.TargetProperty="(Shape.Fill).(SolidColorBrush.Color)">
<SplineColorKeyFrame KeyTime="00:00:00.0" Value="{StaticResource FilledColor}"/>
<SplineColorKeyFrame KeyTime="00:00:01.6" Value="{StaticResource UnfilledColor}"/>
</ColorAnimationUsingKeyFrames>
</Storyboard>
<Storyboard x:Key="Animation2" BeginTime="00:00:00.4" RepeatBehavior="Forever">
<ColorAnimationUsingKeyFrames Storyboard.TargetName="ellipse2" Storyboard.TargetProperty="(Shape.Fill).(SolidColorBrush.Color)">
<SplineColorKeyFrame KeyTime="00:00:00.0" Value="{StaticResource FilledColor}"/>
<SplineColorKeyFrame KeyTime="00:00:01.6" Value="{StaticResource UnfilledColor}"/>
</ColorAnimationUsingKeyFrames>
</Storyboard>
<Storyboard x:Key="Animation3" BeginTime="00:00:00.6" RepeatBehavior="Forever">
<ColorAnimationUsingKeyFrames Storyboard.TargetName="ellipse3" Storyboard.TargetProperty="(Shape.Fill).(SolidColorBrush.Color)">
<SplineColorKeyFrame KeyTime="00:00:00.0" Value="{StaticResource FilledColor}"/>
<SplineColorKeyFrame KeyTime="00:00:01.6" Value="{StaticResource UnfilledColor}"/>
</ColorAnimationUsingKeyFrames>
</Storyboard>
<Storyboard x:Key="Animation4" BeginTime="00:00:00.8" RepeatBehavior="Forever">
<ColorAnimationUsingKeyFrames Storyboard.TargetName="ellipse4" Storyboard.TargetProperty="(Shape.Fill).(SolidColorBrush.Color)">
<SplineColorKeyFrame KeyTime="00:00:00.0" Value="{StaticResource FilledColor}"/>
<SplineColorKeyFrame KeyTime="00:00:01.6" Value="{StaticResource UnfilledColor}"/>
</ColorAnimationUsingKeyFrames>
</Storyboard>
<Storyboard x:Key="Animation5" BeginTime="00:00:01.0" RepeatBehavior="Forever">
<ColorAnimationUsingKeyFrames Storyboard.TargetName="ellipse5" Storyboard.TargetProperty="(Shape.Fill).(SolidColorBrush.Color)">
<SplineColorKeyFrame KeyTime="00:00:00.0" Value="{StaticResource FilledColor}"/>
<SplineColorKeyFrame KeyTime="00:00:01.6" Value="{StaticResource UnfilledColor}"/>
</ColorAnimationUsingKeyFrames>
</Storyboard>
<Storyboard x:Key="Animation6" BeginTime="00:00:01.2" RepeatBehavior="Forever">
<ColorAnimationUsingKeyFrames Storyboard.TargetName="ellipse6" Storyboard.TargetProperty="(Shape.Fill).(SolidColorBrush.Color)">
<SplineColorKeyFrame KeyTime="00:00:00.0" Value="{StaticResource FilledColor}"/>
<SplineColorKeyFrame KeyTime="00:00:01.6" Value="{StaticResource UnfilledColor}"/>
</ColorAnimationUsingKeyFrames>
</Storyboard>
<Storyboard x:Key="Animation7" BeginTime="00:00:01.4" RepeatBehavior="Forever">
<ColorAnimationUsingKeyFrames Storyboard.TargetName="ellipse7" Storyboard.TargetProperty="(Shape.Fill).(SolidColorBrush.Color)">
<SplineColorKeyFrame KeyTime="00:00:00.0" Value="{StaticResource FilledColor}"/>
<SplineColorKeyFrame KeyTime="00:00:01.6" Value="{StaticResource UnfilledColor}"/>
</ColorAnimationUsingKeyFrames>
</Storyboard>
</ControlTemplate.Resources>
<ControlTemplate.Triggers>
<Trigger Property="IsVisible" Value="True">
<Setter Property="Panel.ZIndex" Value="100" />
<Trigger.EnterActions>
<BeginStoryboard Storyboard="{StaticResource Animation0}" x:Name="Storyboard0" />
<BeginStoryboard Storyboard="{StaticResource Animation1}" x:Name="Storyboard1"/>
<BeginStoryboard Storyboard="{StaticResource Animation2}" x:Name="Storyboard2"/>
<BeginStoryboard Storyboard="{StaticResource Animation3}" x:Name="Storyboard3"/>
<BeginStoryboard Storyboard="{StaticResource Animation4}" x:Name="Storyboard4"/>
<BeginStoryboard Storyboard="{StaticResource Animation5}" x:Name="Storyboard5"/>
<BeginStoryboard Storyboard="{StaticResource Animation6}" x:Name="Storyboard6"/>
<BeginStoryboard Storyboard="{StaticResource Animation7}" x:Name="Storyboard7"/>
</Trigger.EnterActions>
<Trigger.ExitActions>
<StopStoryboard BeginStoryboardName="Storyboard0"/>
<StopStoryboard BeginStoryboardName="Storyboard1"/>
<StopStoryboard BeginStoryboardName="Storyboard2"/>
<StopStoryboard BeginStoryboardName="Storyboard3"/>
<StopStoryboard BeginStoryboardName="Storyboard4"/>
<StopStoryboard BeginStoryboardName="Storyboard5"/>
<StopStoryboard BeginStoryboardName="Storyboard6"/>
<StopStoryboard BeginStoryboardName="Storyboard7"/>
</Trigger.ExitActions>
</Trigger>
</ControlTemplate.Triggers>
<Border BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="{TemplateBinding BorderThickness}"
Background="{TemplateBinding Background}">
<Grid>
<Canvas Height="60" Width="60">
<Canvas.Resources>
<Style TargetType="Ellipse">
<Setter Property="Width" Value="15"/>
<Setter Property="Height" Value="15" />
<Setter Property="Fill" Value="#009B9B9B" />
</Style>
</Canvas.Resources>
<Ellipse x:Name="ellipse0" Canvas.Left="1.75" Canvas.Top="21"/>
<Ellipse x:Name="ellipse1" Canvas.Top="7" Canvas.Left="6.5"/>
<Ellipse x:Name="ellipse2" Canvas.Left="20.5" Canvas.Top="0.75"/>
<Ellipse x:Name="ellipse3" Canvas.Left="34.75" Canvas.Top="6.75"/>
<Ellipse x:Name="ellipse4" Canvas.Left="40.5" Canvas.Top="20.75" />
<Ellipse x:Name="ellipse5" Canvas.Left="34.75" Canvas.Top="34.5"/>
<Ellipse x:Name="ellipse6" Canvas.Left="20.75" Canvas.Top="39.75"/>
<Ellipse x:Name="ellipse7" Canvas.Top="34.25" Canvas.Left="7" />
<Ellipse Width="39.5" Height="39.5" Canvas.Left="8.75" Canvas.Top="8" Visibility="Hidden"/>
<Label Content="{Binding Path=WaitMessageText}"
FontSize="17"
Canvas.Left="60.5" Canvas.Top="11.5"
HorizontalContentAlignment="Center"
VerticalAlignment="Center"/>
</Canvas>
</Grid>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</UserControl.Resources>
<Control Style="{StaticResource BusyAnimationStyle}" />
</UserControl>