Problem setting CornerRadius in Generic.xaml

06-20-2009 3:12 PM |

I have been working at creating a very simple Custom Control, using Jeff Prosise's MSDN Magazine article as a starting point.

It has been less than fun. Every time I run my little project, it errors out with

System.Windows.Markup.XamlParseException occurred
  Message="AG_E_UNKNOWN_ERROR [Line: 8 Position: 30]"
  LineNumber=8
  LinePosition=30
  StackTrace:
       at System.Windows.Application.LoadComponent(Object component, Uri resourceLocator)
       at SimpleButtonDemo.Page.InitializeComponent()
       at SimpleButtonDemo.Page..ctor()
  InnerException:

Here is my entire generic.xaml file:

<ResourceDictionary 
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  xmlns:custom="clr-namespace:SimpleButtonDemo;assembly=SimpleButtonDemo"
  xmlns:vsm="clr-namespace:System.Windows;assembly=System.Windows" 
  xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
  xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d">
	<Style TargetType="custom:SimpleButton">
        <Setter Property="Width" Value="200" />
        <Setter Property="Height" Value="100" />
        <Setter Property="Background" Value="Lavender" />
        <Setter Property="BorderBrush" Value="Red" />
        <Setter Property="BorderThickness" Value="4" />
        <!--Setter Property="CornerRadius" Value="4" /-->
        <Setter Property="FontSize" Value="11" />
        <Setter Property="HorizontalAlignment" Value="Center" />
        <Setter Property="VerticalAlignment" Value="Center" />
        <Setter Property="HorizontalContentAlignment" Value="Center" />
        <Setter Property="VerticalContentAlignment" Value="Center" />
        <Setter Property="Margin" Value="6" />

        <Setter Property="Template">
			<Setter.Value>
				<ControlTemplate TargetType="custom:SimpleButton">
                    <Grid x:Name="RootElement">
                        <Grid.Resources>
                            <Storyboard x:Key="MouseEnterAnimation">
                                <DoubleAnimation Storyboard.TargetName="BorderElement" Storyboard.TargetProperty="Opacity" From="0" To="0.2" Duration="0:0:0.5" />
                            </Storyboard>
                            <Storyboard x:Key="MouseLeaveAnimation">
                                <DoubleAnimation Storyboard.TargetName="BorderElement" Storyboard.TargetProperty="Opacity" From="0.2" To="0" Duration="0:0:0.5" />
                            </Storyboard>
                        </Grid.Resources>
                        <Border x:Name="BorderElement" BorderBrush="{TemplateBinding BorderBrush}"
                                Background="{TemplateBinding Background}"
                                BorderThickness="{TemplateBinding BorderThickness}"
                                Height="{TemplateBinding Height}"
                                Width="{TemplateBinding Width}"
                                CornerRadius="6"
                                   >
                            <ContentPresenter Content="{TemplateBinding Content}"
 							    HorizontalAlignment="{TemplateBinding HorizontalAlignment}" 
                                VerticalAlignment="{TemplateBinding VerticalAlignment}"
                                Margin ="{TemplateBinding Margin}"
                                ContentTemplate="{TemplateBinding ContentTemplate}"
							     />
                        </Border>
                    </Grid>
				</ControlTemplate>
			</Setter.Value>
		</Setter>
	</Style>
</ResourceDictionary>

 I finally tracked down the offending line:

<!--Setter Property="CornerRadius" Value="4" /-->

When I uncomment this line I get the error reported above. If I leave the line commented out, everything works fine.

Helen

Re: Problem setting CornerRadius in Generic.xaml

06-20-2009 4:53 PM |

Button does not have a CornerRadius property, and my guess is neither does your SimpleButton class: http://msdn.microsoft.com/en-us/library/system.windows.controls.button_properties(VS.95).aspx

Create a CornerRadius dependency property on your SimpleButton class and set it on the Border element in the control template: CornerRadius="{TemplateBinding CornerRadius}".

Re: Problem setting CornerRadius in Generic.xaml

06-20-2009 5:05 PM |

OK that makes sense. "SimpleButton" actually inherits from ContentControl, so what you are saying is that any property of a contained control in the template that I want to set needs to have a dependency property registered?

Is there a recommended way of handling such properties? For example, suppose my "SimpleButton" template contains two child controls (C1 & C2) that both have a "Width" property. Do I register 2 dependency properties for C1.Width and C2.Width? Is there a better way?

Thanks

Re: Re: Re: Problem setting CornerRadius in Generic.xaml

06-20-2009 5:20 PM |

I only hard-coded it because I couldn't get it to work. Will take your excellent advice and set it using template binding.

Thanks for the quick reply!