This is code i have an exprience when i want to create a round button in my application i have used this code. this is one way of the create round button in wpf application. if we want change the color and Radial Gradient color and also we can able to apply the Transform using opacity. its very useful i have past the following code.
<Button Width="100" Height="100">
<Button.Template>
<ControlTemplate TargetType="Button">
<Grid>
<Ellipse Stroke="#5ECF5E"
StrokeThickness="2">
<Ellipse.Fill>
<RadialGradientBrush GradientOrigin="0.496,1.052">
<RadialGradientBrush.RelativeTransform>
<TransformGroup>
<ScaleTransform CenterX="0.5" CenterY="0.5" ScaleX="1.5" ScaleY="1.5"/>
<TranslateTransform X="0.02" Y="0.2"/>
</TransformGroup>
</RadialGradientBrush.RelativeTransform>
<GradientStop Offset="1" Color="#5ECF5E"/>
<GradientStop Offset="0.2" Color="#FFFFFFFF"/>
</RadialGradientBrush>
</Ellipse.Fill>
</Ellipse>
<ContentPresenter HorizontalAlignment="Center"
VerticalAlignment="Center"/>
</Grid>
</ControlTemplate>
</Button.Template>
</Button>
another one way to create the round button.
<Button Width="100" Height="100" Content="Abcd">
<Button.Template>
<ControlTemplate TargetType="{x:Type Button}">
<Grid>
<Ellipse Fill="Red"/>
<ContentPresenter Content="{TemplateBinding Content}" HorizontalAlignment="Center" VerticalAlignment="Center"/>
</Grid>
</ControlTemplate>
</Button.Template>
</Button>
this code create an rectangle button with color and Radial Gradient color and also we can able to apply the Transform using opacity.
<UserControl x:Class="WindowsFormsApplication8.UserControl1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Height="154" Width="177">
<Grid>
<Rectangle Name="rectangle1" Stroke="Black" RadiusX="10" RadiusY="10" >
</Rectangle>
<Button Name="rectangle2" Foreground="Black" Margin="3,3,3,3" >
<Button.Background >
<LinearGradientBrush StartPoint="0,0" EndPoint="1,1">
<GradientStop Color="Green" Offset="0.0" />
<GradientStop Color="White" Offset="0.9" />
</LinearGradientBrush>
</Button.Background>
</Button>
</Grid>
</UserControl>
