docs-desktop/dotnet-desktop-guide/net/wpf/themes/snippets/how-to-create-apply-template/csharp/MainWindow.xaml

<Window x:Class="IntroToStylingAndTemplating.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:IntroToStylingAndTemplating"
        mc:Ignorable="d"
        Title="Template Intro Sample" Loaded="WindowLoaded" SizeToContent="WidthAndHeight" MinWidth="250">
    <Window.Resources>
        <ControlTemplate x:Key="roundbutton" TargetType="Button">
            <Grid>
                <VisualStateManager.VisualStateGroups>
                    <VisualStateGroup Name="CommonStates">
                        <VisualState Name="Normal">
                            <Storyboard>
                                <ColorAnimation Storyboard.TargetName="backgroundElement" 
                                    Storyboard.TargetProperty="(Shape.Fill).(SolidColorBrush.Color)"
                                    To="{TemplateBinding Background}"
                                    Duration="0:0:0.3"/>
                            </Storyboard>
                        </VisualState>
                        <VisualState Name="MouseOver">
                            <Storyboard>
                                <ColorAnimation Storyboard.TargetName="backgroundElement" 
                                    Storyboard.TargetProperty="(Shape.Fill).(SolidColorBrush.Color)" 
                                    To="Yellow" 
                                    Duration="0:0:0.3"/>
                            </Storyboard>
                        </VisualState>
                    </VisualStateGroup>
                </VisualStateManager.VisualStateGroups>
                <Ellipse Name="backgroundElement" Fill="{TemplateBinding Background}" Stroke="{TemplateBinding Foreground}" />
                <ContentPresenter x:Name="contentPresenter" HorizontalAlignment="Center" VerticalAlignment="Center" />
            </Grid>
        </ControlTemplate>
    </Window.Resources>
    <StackPanel Margin="10">
        <Label>Unstyled Button</Label>
        <Button>Button 1</Button>
        <Label>Rounded Button</Label>
        <Button Template="{StaticResource roundbutton}" Width="65" Height="65" Click="Button_Click">Button 2</Button>
    </StackPanel>
</Window>