自定义控件事件不起作用

我创建了一个具有悬停/单击效果的自定义按钮。我不知道为什么鼠标事件不起作用。类定义中的重写事件处理程序仍然有效。

这是自定义控件的XAML：

<ResourceDictionary
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:CSOCodeBox_WPF">

<Style TargetType="{x:Type local:HoverButton}">
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type local:HoverButton}">
                 <Rectangle x:Name="btnImage" HorizontalAlignment="Left" VerticalAlignment="Top" Width="{TemplateBinding Width}" Height="{TemplateBinding Height}">
                     <Rectangle.Fill>
                         <ImageBrush ImageSource="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Image}"/>
                     </Rectangle.Fill>
                 </Rectangle>
                 <ControlTemplate.Triggers>
                    <Trigger Property="IsMouseOver" Value="True">
                        <Setter TargetName="btnImage" Property="Fill">
                            <Setter.Value>
                                <ImageBrush ImageSource="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=HoverImage}"/>
                            </Setter.Value>
                        </Setter>
                    </Trigger>
                    <Trigger Property="IsMouseCaptured" Value="True">
                        <Setter TargetName="btnImage" Property="Fill">
                            <Setter.Value>
                                <ImageBrush ImageSource="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=PressImage}"/>
                            </Setter.Value>
                        </Setter>
                    </Trigger>                        
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

将控件添加到主窗口：

<my:HoverButton x:Name="hoverButton1" Width="201" Height="121" Canvas.Left="235" Canvas.Top="500" Image="/CSOCodeBox_WPF;component/GFX/Button_None.png" HoverImage="/CSOCodeBox_WPF;component/GFX/Button_Ready.png" PressImage="/CSOCodeBox_WPF;component/GFX/Button_Clicking.png" MouseDown="hoverButton1_MouseDown_1"></my:HoverButton>

事件：

        private void hoverButton1_MouseDown_1(object sender, MouseButtonEventArgs e)
    {
        MessageBox.Show("Button clicked");
    }