Question

I want to adjust the corner radius on my buttons. I can do this by creating a separate style resource and setting the corner radius of a border in the template. However, I have to create a separate style for every variation.

What I want is an actual CornerRadius property that I can set for each button and not have to create another style every time I want a different corner radius.

Is my only solution here to create a custom control?

Answer 1

After some playing around I have concluded the easiest way to do this is bind to an attached property of type ConerRadius.

In the template you bind the Corner Radius like this:

<Border x:Name="Background" CornerRadius="{TemplateBinding Corner.Radii}" 

You use it like this:

<Button Corner.Radii="10"

or even like this:

<Button Corner.Radii="2, 10, 10, 2"

Examples:

Full code follows:

Attached property class:

public static class Corner
{
    public static readonly DependencyProperty RadiiProperty = DependencyProperty.RegisterAttached(
      "Radii",
      typeof(CornerRadius),
      typeof(UIElement), null);

    public static void SetRadii(UIElement element, CornerRadius value)
    {
        element.SetValue(RadiiProperty, value);
    }

    public static CornerRadius GetRadii(UIElement element)
    {
        return (CornerRadius)element.GetValue(RadiiProperty);
    }
}

Sample page using it:

Note: the button template is included inline in full for this example

<UserControl x:Class="CornerBehaviorTest.MainPage"
    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:CornerBehaviorTest="clr-namespace:CornerBehaviorTest" mc:Ignorable="d"
    d:DesignHeight="300" d:DesignWidth="400">
    <UserControl.Resources>
        <Style TargetType="Button">
            <Setter Property="Background" Value="AliceBlue"/>
            <Setter Property="Foreground" Value="Red"/>
            <Setter Property="Padding" Value="3"/>
            <Setter Property="BorderThickness" Value="1"/>
            <Setter Property="BorderBrush">
                <Setter.Value>
                    <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
                        <GradientStop Color="#FFA3AEB9" Offset="0"/>
                        <GradientStop Color="#FF8399A9" Offset="0.375"/>
                        <GradientStop Color="#FF718597" Offset="0.375"/>
                        <GradientStop Color="#FF617584" Offset="1"/>
                    </LinearGradientBrush>
                </Setter.Value>
            </Setter>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="Button">
                        <Grid>
                            <VisualStateManager.VisualStateGroups>
                                <VisualStateGroup x:Name="CommonStates">
                                    <VisualState x:Name="Normal"/>
                                    <VisualState x:Name="MouseOver">
                                        <Storyboard>
                                            <DoubleAnimation Duration="0" Storyboard.TargetName="BackgroundAnimation" Storyboard.TargetProperty="Opacity" To="1"/>
                                            <ColorAnimation Duration="0" Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Rectangle.Fill).(GradientBrush.GradientStops)[1].(GradientStop.Color)" To="#F2FFFFFF"/>
                                            <ColorAnimation Duration="0" Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Rectangle.Fill).(GradientBrush.GradientStops)[2].(GradientStop.Color)" To="#CCFFFFFF"/>
                                            <ColorAnimation Duration="0" Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Rectangle.Fill).(GradientBrush.GradientStops)[3].(GradientStop.Color)" To="#7FFFFFFF"/>
                                        </Storyboard>
                                    </VisualState>
                                    <VisualState x:Name="Pressed">
                                        <Storyboard>
                                            <ColorAnimation Duration="0" Storyboard.TargetName="Background" Storyboard.TargetProperty="(Border.Background).(SolidColorBrush.Color)" To="#FF6DBDD1"/>
                                            <DoubleAnimation Duration="0" Storyboard.TargetName="BackgroundAnimation" Storyboard.TargetProperty="Opacity" To="1"/>
                                            <ColorAnimation Duration="0" Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Rectangle.Fill).(GradientBrush.GradientStops)[0].(GradientStop.Color)" To="#D8FFFFFF"/>
                                            <ColorAnimation Duration="0" Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Rectangle.Fill).(GradientBrush.GradientStops)[1].(GradientStop.Color)" To="#C6FFFFFF"/>
                                            <ColorAnimation Duration="0" Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Rectangle.Fill).(GradientBrush.GradientStops)[2].(GradientStop.Color)" To="#8CFFFFFF"/>
                                            <ColorAnimation Duration="0" Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Rectangle.Fill).(GradientBrush.GradientStops)[3].(GradientStop.Color)" To="#3FFFFFFF"/>
                                        </Storyboard>
                                    </VisualState>
                                    <VisualState x:Name="Disabled">
                                        <Storyboard>
                                            <DoubleAnimation Duration="0" Storyboard.TargetName="DisabledVisualElement" Storyboard.TargetProperty="Opacity" To=".55"/>
                                        </Storyboard>
                                    </VisualState>
                                </VisualStateGroup>
                                <VisualStateGroup x:Name="FocusStates">
                                    <VisualState x:Name="Focused">
                                        <Storyboard>
                                            <DoubleAnimation Duration="0" Storyboard.TargetName="FocusVisualElement" Storyboard.TargetProperty="Opacity" To="1"/>
                                        </Storyboard>
                                    </VisualState>
                                    <VisualState x:Name="Unfocused" />
                                </VisualStateGroup>
                            </VisualStateManager.VisualStateGroups>
                            <Border x:Name="Background" CornerRadius="{TemplateBinding CornerBehaviorTest:Corner.Radii}" Background="White" BorderThickness="{TemplateBinding BorderThickness}" BorderBrush="{TemplateBinding BorderBrush}">
                                <Grid Background="{TemplateBinding Background}"  Margin="1">
                                    <Border Opacity="0"  x:Name="BackgroundAnimation" Background="#FF448DCA" />
                                    <Rectangle x:Name="BackgroundGradient" >
                                        <Rectangle.Fill>
                                            <LinearGradientBrush StartPoint=".7,0" EndPoint=".7,1">
                                                <GradientStop Color="#FFFFFFFF" Offset="0" />
                                                <GradientStop Color="#F9FFFFFF" Offset="0.375" />
                                                <GradientStop Color="#E5FFFFFF" Offset="0.625" />
                                                <GradientStop Color="#C6FFFFFF" Offset="1" />
                                            </LinearGradientBrush>
                                        </Rectangle.Fill>
                                    </Rectangle>
                                </Grid>
                            </Border>
                            <ContentPresenter
                              x:Name="contentPresenter"
                              Content="{TemplateBinding Content}"
                              ContentTemplate="{TemplateBinding ContentTemplate}"
                              VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
                              HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
                              Margin="{TemplateBinding Padding}"/>
                            <Rectangle x:Name="DisabledVisualElement" RadiusX="3" RadiusY="3" Fill="#FFFFFFFF" Opacity="0" IsHitTestVisible="false" />
                            <Rectangle x:Name="FocusVisualElement" RadiusX="2" RadiusY="2" Margin="1" Stroke="#FF6DBDD1" StrokeThickness="1" Opacity="0" IsHitTestVisible="false" />
                        </Grid>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </UserControl.Resources>
        <Grid x:Name="LayoutRoot" Background="White">
        <Button CornerBehaviorTest:Corner.Radii="10,5,5,5" Content="Button" Height="40" HorizontalAlignment="Left" Margin="130,22,0,0" Name="button1" VerticalAlignment="Top" Width="73" />
    </Grid>
</UserControl>

Old answer

You have several options:

• Create the various radii types you want using application resources and use StaticResource Binding (Expression Blend just lets you do this in the GUI which is nice, but you can do it manually)
• You can create an attached behaviour and have a single Radius property that sets all 4 corners.
• Create an attached dependency property (bind the template to a new Radius property)
• You can create a custom control as you suggest.