Style.Triggers vs ControlTemplate.Triggers

Question

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 1

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 documentation). But that would only matter if you use both trigger types.