Not able to override button style from app.xaml in WPF

Question

I stuck in very strange problem and I could not find solution to it. I tried almost all the possible ways (even delete and recreate solution) to solve this.

ISSUE

I am trying to override default style of control in a WPF app. I defined all the resouces and styles in App.xaml. Problem is, a button foreground color is not getting override runtime. Suprisingly, it show overriden color (White) in VS designer but when I run app, it becomes black (may be default).

There is no other code in app that changes button style.

Additional Info : Buttons are in a Usercontrol and its loaded on MainWindow's ContentControl.

<SolidColorBrush x:Key="WhiteBrush" Color="#FFFFFF"/>
<SolidColorBrush x:Key="BlackBrush" Color="#000000"/>
<SolidColorBrush x:Key="ActiveBrush" Color="#3A71C5"/>
<SolidColorBrush x:Key="HoverBrush" Color="#0071C5"/>
<SolidColorBrush x:Key="PressBrush" Color="#3A8BF4"/>
<SolidColorBrush x:Key="DefaultBrush" Color="#0071F9"/>
<SolidColorBrush x:Key="DisabledBrush" Color="#F4F4F4"/>


<Style TargetType="{x:Type Button}">
    <Setter Property="Background" Value="{StaticResource ActiveBrush}"/>
    <Setter Property="Foreground" Value="{StaticResource WhiteBrush}"/>
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type Button}">
                <Border Background="{TemplateBinding Background}" BorderBrush="Transparent" BorderThickness="0">
                    <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center" />
                </Border>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
    <Style.Triggers>
        <Trigger Property="IsMouseOver" Value="True">
            <Setter Property="Background" Value="{StaticResource HoverBrush}"/>
        </Trigger>
        <Trigger Property="IsPressed" Value="True">
            <Setter Property="Background" Value="{StaticResource PressBrush}"/>
        </Trigger>
        <Trigger Property="IsEnabled" Value="False">
            <Setter Property="Background" Value="{StaticResource DisabledBrush}"/>
        </Trigger>
    </Style.Triggers>

</Style>

Buttons in VS Designer

Buttons in app runtime

Answer 1

The issue could be that you have some other style which gets applied to some nested control of your button (e.g. TextBlock).

I pasted your snippet in a sample WPF app and wrapped a Button in a custom UserControl. I tested it and showed correctly in both design view and runtime.

Then I added the following style in App.xaml:

<Style TargetType="{x:Type TextBlock}">
     <Setter Property="Foreground" Value="Red"/>
</Style>

and the button was showing red text.

So the problem could be some other style for other controls which is overriding some parts of your Button template.

---

EDIT

A possible solution could be to explicitly define the Button content in the control itself:

<Button>
    <TextBlock Foreground="{StaticResource WhiteBrush}">Test</TextBlock>
</Button>

There are probably more elegant ways to do this, but I couldn't come up with anything else at the moment.