WPF 从 Button 继承为 MyUserControl

Answer 1

正如emocht提到的，我忘记在ControlTemplate中指定TargetType：

<ControlTemplate TargetType="Button">
    <Border Background="#F6F9FC" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="4"
        CornerRadius="20" x:Name="Border" Padding="22 0">
        <ContentPresenter Content="{TemplateBinding Content}" />
    </Border>
</ControlTemplate>