I am writing a WPF control that subclasses a Button. I then provide a default style in Themes\generic.xaml, that looks like this (simplified):
<Style TargetType="{x:Type WPFControls:MyButton}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type WPFControls:MyButton}">
<Button
x:Name="PART_Button"
Background="{TemplateBinding Background}"
BorderBrush="{TemplateBinding BorderBrush}"
/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
I would like the user to have the opportunity to change the control's background, but if he doesn't, I'd like to provide default value. How do I do it?
When I do it like in the posted code, the Background and BorderBrush is null (= nonexistent) unless user explicitly specifies them (which effectively forces user to always provide some value), but the standard windows controls (like Button) provide a default look, that can still be customized by user. How to do this in my control?
Thank you!
Solution by Michael Morton:
You can provide defaults as setters in style:
<Style TargetType="{x:Type TestTemplate:MyButton}">
<Setter Property="Background" Value="Red" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type TestTemplate:MyButton}">
<Button
x:Name="PART_Button"
IsEnabled="{TemplateBinding IsEnabled}"
Content="{TemplateBinding Content}"
Background="{TemplateBinding Background}"
/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
Usage:
<StackPanel>
<TestTemplate:MyButton Background="Blue">Explicitly blue</TestTemplate:MyButton>
<TestTemplate:MyButton>Naturally red</TestTemplate:MyButton>
</StackPanel>