First specify the Overridesdefaultstyle property as true;
then add the style;
Rewrite ControlTemplate;
<window.resources> <Stylex:key= "Userbuttonstyle"TargetType= "button"> <Setter Property= "Overridesdefaultstyle"Value= "True" /> <Setter Property= "Cursor"Value= "Hand" /> <Setter Property= "Padding"Value= "5 3" /> <Setter Property= "Background"Value= "LightBlue" /> <Setter Property= "Template"> <Setter.value> <ControlTemplateTargetType= "button"> <BorderName= "Border"borderthickness= "0"BorderBrush= "Black"Padding="{TemplateBinding Padding}"Background="{TemplateBinding Background}"> <ContentPresenterHorizontalAlignment= "Center"VerticalAlignment= "Center" /> </Border> <controltemplate.triggers> <Trigger Property= "IsMouseOver"Value= "True"> <Setter Property= "Opacity"Value= "0.8" /> </Trigger> </controltemplate.triggers> </ControlTemplate> </Setter.value> </Setter> </Style></window.resources>
WPF overriding button styles