How to bind Opacity value based on opacity of the object from another ControlTemplate?

I’d like to find out how to bind the opacity of the object that is part of the ControlTemplate to the object that is part of another ControlTemplate. I tried this but it is not doing anything.

Image x:Name="PART_IconHover" Source="{Binding IconHover}" Opacity="{Binding Opacity, ElementName=border, Mode=OneWay}" />

Below is the code of two ControlTemplates:

<Setter Property="Template">
<Setter.Value>
    <ControlTemplate TargetType="{x:Type Button}">
        <Border x:Name="border" BorderBrush="#FF6E6E6E" BorderThickness="0.5" Opacity="0" Background="#00000000">
            <VisualStateManager.VisualStateGroups>
                <VisualStateGroup x:Name="CommonStates">
                    <VisualState x:Name="Normal"/>
                    <VisualState x:Name="MouseOver">
                        <Storyboard>
                            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Opacity)" Storyboard.TargetName="border">
                                <EasingDoubleKeyFrame KeyTime="0" Value="1"/>
                            </DoubleAnimationUsingKeyFrames>
                                                                </Storyboard>
                    </VisualState>
                    <VisualState x:Name="Pressed"/>
                    <VisualState x:Name="Disabled"/>
                </VisualStateGroup>
            </VisualStateManager.VisualStateGroups>
        </Border>
        <ControlTemplate.Triggers>
            <Trigger Property="IsKeyboardFocused" Value="true"/>
            <Trigger Property="ToggleButton.IsChecked" Value="true"/>
            <Trigger Property="IsEnabled" Value="false">
                <Setter Property="Foreground" Value="#ADADAD"/>
            </Trigger>
        </ControlTemplate.Triggers>
    </ControlTemplate>
</Setter.Value>

I want to b开发者_C百科ind the opacity to the image in the ControlTemplate below

<ControlTemplate x:Key="ThumbnailContainerTemplate" TargetType="{x:Type ContentControl}">
    <Border x:Name="PART_Border" BorderThickness="1" BorderBrush="#FFd9d9d9" Opacity="0" />
    <Grid Margin="10">   
            <Image x:Name="PART_IconHover" Source="{Binding IconHover}" Opacity="{Binding Opacity, ElementName=border, Mode=OneWay}" />
    </Grid>

Any ideas are highly appreciated. Thank you in advance!

I don't think that you can bind to elements inside templates like that. The binding system isn't able to find them.

If you just need a numeric value somewhere in your xaml that you want everything to use, you can just add one like this:

<sys:Double x:Key="Opacity">.5</sys:Double>

Then just have everything bind to that. You'll need to add the sys namespace

xmlns:sys="clr-namespace:System;assembly=mscorlib"

As mdm20 said, you can't bind to elements inside templates from outside the template since a template is just used to build up a control. For instance, several Buttons could use the Template in your example so which Button would the ContentControl bind to?

I can't see a re-usable solution to this but one thing that comes to mind is to set the Binding in code behind once the Controls have finished loading like this

private void Window_Loaded(object sender, RoutedEventArgs e)
{
    Border border = myButton.Template.FindName("border", myButton) as Border;
    Image PART_IconHover = contentControl.Template.FindName("PART_IconHover", contentControl) as Image;

    Binding opacityBinding = new Binding("Opacity");
    opacityBinding.Mode = BindingMode.OneWay;
    opacityBinding.Source = border;
    PART_IconHover.SetBinding(Image.OpacityProperty, opacityBinding);
}

Update
Two Controls binding to the border in a Button template. The binding is made in the Control_Loaded event handler.

<ContentControl ...
                Loaded="Control_Loaded">
    <ContentControl.Style>
        <Style TargetType="ContentControl">
            <Setter Property="Template" Value="{StaticResource contentTemplate}"/>
        </Style>
    </ContentControl.Style>
</ContentControl>
<ContentControl ...
                Loaded="Control_Loaded">
    <ContentControl.Style>
        <Style TargetType="ContentControl">
            <Setter Property="Template" Value="{StaticResource contentTemplate}"/>
        </Style>
    </ContentControl.Style>
</ContentControl>

private void Control_Loaded(object sender, RoutedEventArgs e)
{
    Border border = myButton.Template.FindName("border", myButton) as Border;
    Control control = sender as Control;
    Image PART_IconHover = control.Template.FindName("PART_IconHover", control) as Image;

    Binding opacityBinding = new Binding("Opacity");
    opacityBinding.Mode = BindingMode.OneWay;
    opacityBinding.Source = border;
    PART_IconHover.SetBinding(Image.OpacityProperty, opacityBinding);
}