WPF 按钮背景色渐变（从四周到中间渐变）
<Style x:Key="RadioButtonMenuStyle" TargetType="RadioButton">
<Setter Property="GroupName" Value="MenuGroup" />
<Setter Property="Width" Value="180" />
<Setter Property="Height" Value="45" />
<Setter Property="Background" Value="#3AADE8" />
<Setter Property="BorderThickness" Value="0" />
<Setter Property="FontSize" Value="14" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="RadioButton">
<Border Background="{TemplateBinding Background}" BorderThickness="{TemplateBinding BorderThickness}" BorderBrush="{TemplateBinding BorderBrush}">
<ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center" />
</Border>
<ControlTemplate.Triggers>
<Trigger Property="IsChecked" Value="true">
<Setter Property="Background" >
<Setter.Value>
<RadialGradientBrush Center="0.5,0.5" GradientOrigin="0.5,0.5" RadiusX="0.99" RadiusY="0.99">
<GradientStop Color="Transparent"/>
<GradientStop Color="#0DE2FC" Offset="0.90"/>
<GradientStop Color="Transparent" Offset="0.162"/>
</RadialGradientBrush>
</Setter.Value>
</Setter>
<Setter Property="Foreground" Value="White"/>
</Trigger>
<Trigger Property="IsMouseOver" Value="true">
<Setter Property="Background" >
<Setter.Value>
<RadialGradientBrush Center="0.5,0.5" GradientOrigin="0.5,0.5" RadiusX="0.99" RadiusY="0.99">
<GradientStop Color="Transparent"/>
<GradientStop Color="#0DE2FC" Offset="0.90"/>
<GradientStop Color="Transparent" Offset="0.162"/>
</RadialGradientBrush>
</Setter.Value>
</Setter>
<Setter Property="Foreground" Value="White"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Border Background="#0091DB" Width="180" Height="45">
<RadioButton Style="{StaticResource RadioButtonMenuStyle}" >
背景色从四周向中间渐变
</RadioButton>
</Border>