DeMama DeMama - 25 days ago 6
C# Question

Style.Triggers vs ControlTemplate.Triggers

When should I choose

Style.Triggers
and when should I choose
ControlTemplate.Triggers
? Are there any benefits using one over another?

Say I have these styles that achieve the same result:

<Style TargetType="{x:Type Button}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Button}">
<ControlTemplate.Triggers>
...
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>

<Style TargetType="{x:Type Button}">
<Setter Property="Template">
...
</Setter>
<Style.Triggers>
...
</Style.Triggers>
</Style>

Answer

Update from Background does not change of button C# WPF the Button in windows 8 does use a ControlTemplate.Trigger for IsMouseOver so there are cases where ControlTemplate may need to be completely overwritten to get the desired functionality. So that would be a case where you need to use ControlTemplate triggers over Style triggers.

You may not always need to override the default ControlTemplate. Say you have a control and you want all the MyTextControl to have a a blue Foreground when IsMouseOver is true and leave everything else as default. You could use something like this:

<Style TargetType="{x:Type MyTextControl}">
    <Style.Triggers>
        <Trigger Property="IsMouseOver" Value="True">
            <Setter Property="Foreground" Value="Blue"/>
        </Trigger>
    </Style.Triggers>
</Style>

If you wanted to use the ControlTemplate.Triggers you would need to copy the default MyTextControl Template or else you would end up with no visual.

Aside from that I think the only difference is that Style.Triggers has a lower precedence than ControlTemplate.Triggers (Precedence documantation). But that would only matter if you use both trigger types.