Binding Path Fill to Button Foreground in ContentPresenter

Question

I have a Button Style with a Template containing a ContentPresenter, in which I am attempting to bind the Fill of a Path to the Foreground of a button:

<!-- This is inside the template of a button style -->
<ContentPresenter>
 <ContentPresenter.Resources>
  <Style TargetType="{x:Type Path}">
   <Setter Property="Fill" Value="{Binding Path=Foreground, RelativeSource={RelativeSource AncestorType=Button}}"/>
   </Style>
  </ContentPresenter.Resources>
</ContentPresenter>

I also have a Path with no Fill set, that I can reference in the button as the content, like so:

<Button Style="{DynamicResource MyButtonStyle}" Content="{DynamicResource PathIcon}" Foreground="Blue"/>

I would expect the Path inside the button to be blue, but it isn't... it doesn't grab the foreground from the button.

How can I get the Path to bind to the color of the button?

Thank you!

P.S.:

If I put a hardcoded color in the Value (i.e. Value="Red"), the Path inside the button is red... so I know that works...

<ContentPresenter>
 <ContentPresenter.Resources>
  <Style TargetType="{x:Type Path}">
   <Setter Property="Fill" Value="Red"/>
   </Style>
  </ContentPresenter.Resources>
</ContentPresenter>

---

Edit:

Here is the complete Style and ControlTemplate:

<Style x:Key="Button_Style" TargetType="{x:Type Button}">
        <Setter Property="Foreground" Value="{StaticResource White_Brush}"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type Button}">
                    <Grid x:Name="grid" Background="Transparent">
                        <ContentPresenter>
                            <ContentPresenter.Resources>
                                <Style TargetType="{x:Type Path}">
                                    <Setter Property="Fill" Value="{Binding Path=Foreground, RelativeSource={RelativeSource AncestorType=Button}}"/>
                                </Style>
                            </ContentPresenter.Resources>
                        </ContentPresenter>
                    </Grid>
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsMouseOver" Value="True">
                               <!-- Should affect Text as well as Paths in the Content property of the button! -->                              
                               <Setter Property="Foreground" Value="{StaticResource Black_Brush}"/>
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

Answer 1

Okay, let's order:

it doesn't grab the foreground from the button.

In styles this construction:

RelativeSource={RelativeSource AncestorType=Button}

will not work, because the Style is just the collection of setters, he does not know about control, are there, specifically about the content of the visual tree. Because RelativeSource should refer to the items above in the visual tree. For this purpose, usually using DataTemplate or ControlTemplate.

If I put a hardcoded color in the Value (i.e. Value="Red")

Yes, in this case, will be working, and always better to create the design of the form:

<SolidColorBrush x:Key="MyButtonColor" Color="Blue" />

And use it for control, like Button:

<Button Background="{StaticResource MyButtonColor}" ... />

and in Style or elsewhere:

<Setter Property="Fill" Value="{StaticResource MyButtonColor}" />   

That is, it is better not to depend on the element parameters (background color, etc.) located in a visual tree, because it can:

• May move to another panel (Grid, StackPanel) or UserControl
• May leave from the project

And brushes in the as resources will always be in one place, changing them in this place, all the elements of their pick up. Also colors can be stored in a special data model that does not depend on the specific technical implementations (resources, variables) in which the data can come from an external source, such as the project/config settings.

If possible, it is better to avoid the use of dynamic resources due to unnecessary use of system perfomance (and in some cases memory leaks), in your cases they are not needed.

Dynamic resources are usually explicitly defined for SolidColorBrush and another species brushes, because by default they are frozen, and they not recommended changed because of the above mentioned reasons (memory leaks). More information can be found here:

Freezable Objects Overview on MSDN

Edit

As I understand it, you want to make universal Style for Button to make the contents of Path or Text (in the case of simultaneous use will be easier). As I have already mentioned above, RelativeSource should be around ControlTemplate, therefore, the Path will be in the Grid with the ContentPresenter.

To style knew, which is provided for the text or for the path, to the Tag (optional property) indicates two properties: OnlyText or OnlyPath.

To set the data for the Path, I've created a attached dependency property, and prescribed it in the ControlTemplate.

Below is a complete example:

XAML

<Window x:Class="ButtonPathHelp.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:ButtonPathHelp"
    xmlns:sys="clr-namespace:System;assembly=mscorlib"
    WindowStartupLocation="CenterScreen"
    Title="MainWindow" Height="350" Width="525">

    <Window.Resources>
        <SolidColorBrush x:Key="Green_Brush" Color="Green" />
        <SolidColorBrush x:Key="Black_Brush" Color="Black" />

        <Style x:Key="Button_Style" TargetType="{x:Type Button}">
            <Setter Property="Foreground" Value="{StaticResource Green_Brush}" />
            <Setter Property="HorizontalAlignment" Value="Center" />
            <Setter Property="VerticalAlignment" Value="Center" />

            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type Button}">
                        <Grid x:Name="grid">
                            <ContentPresenter x:Name="MyContent"
                                              Content="{TemplateBinding Content}"
                                              HorizontalAlignment="{TemplateBinding HorizontalAlignment}"
                                              VerticalAlignment="{TemplateBinding VerticalAlignment}" />

                            <Path x:Name="MyPath" 
                                  SnapsToDevicePixels="True" 
                                  Width="20" 
                                  Height="18" 
                                  Stretch="Fill" 
                                  Fill="{Binding Path=Foreground, RelativeSource={RelativeSource AncestorType={x:Type Button}}}" 
                                  Data="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=(local:MyDependencyClass.DataForPath)}" />
                        </Grid>

                        <ControlTemplate.Triggers>
                            <Trigger Property="IsMouseOver" Value="True">
                                <Setter Property="Foreground" Value="{StaticResource Black_Brush}"/>
                            </Trigger>

                            <Trigger Property="Tag" Value="OnlyText">
                                <Setter TargetName="MyPath" Property="Visibility" Value="Collapsed" />
                                <Setter TargetName="MyContent" Property="Visibility" Value="Visible" />
                            </Trigger>

                            <Trigger Property="Tag" Value="OnlyPath">
                                <Setter TargetName="MyPath" Property="Visibility" Value="Visible" />
                                <Setter TargetName="MyContent" Property="Visibility" Value="Collapsed" />
                            </Trigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </Window.Resources>

    <WrapPanel>
        <WrapPanel.Resources>
            <sys:String x:Key="Save">
                F1 M 20.5833,20.5833L 55.4167,20.5833L 55.4167,55.4167L 45.9167,55.4167L 45.9167,44.3333L 30.0833,44.3333L 30.0833,
                55.4167L 20.5833,55.4167L 20.5833,20.5833 Z M 33.25,55.4167L 33.25,50.6667L 39.5833,50.6667L 39.5833,55.4167L 33.25,
                55.4167 Z M 26.9167,23.75L 26.9167,33.25L 49.0833,33.25L 49.0833,23.75L 26.9167,23.75 Z
            </sys:String>

            <sys:String x:Key="Search">
                F1 M 23.4454,49.2637L 31.7739,41.1598C 30.6986,39.2983 30.4792,37.1377 30.4792,34.8333C 30.4792,27.8377 35.7544,
                22.1667 42.75,22.1667C 49.7456,22.1667 55.4167,27.8377 55.4167,34.8333C 55.4167,41.8289 49.7456,47.1042 42.75,
                47.1042C 40.5639,47.1042 38.5072,46.9462 36.7125,45.9713L 28.3196,54.1379C 27.0829,55.3746 24.6821,55.3746 23.4454,
                54.1379C 22.2088,52.9013 22.2088,50.5004 23.4454,49.2637 Z M 42.75,26.9167C 38.3777,26.9167 34.8333,30.4611 34.8333,
                34.8333C 34.8333,39.2056 38.3777,42.75 42.75,42.75C 47.1222,42.75 50.6667,39.2056 50.6667,34.8333C 50.6667,
                30.4611 47.1222,26.9167 42.75,26.9167 Z
            </sys:String>
        </WrapPanel.Resources>

        <Button Name="SaveButton"
                Style="{StaticResource Button_Style}" 
                Tag="OnlyPath"
                local:MyDependencyClass.DataForPath="{StaticResource Save}"
                Margin="10" />

        <Button Name="JustText"
                Style="{StaticResource Button_Style}" 
                Tag="OnlyText"
                Content="Just Text"
                Margin="10" />

        <Button Name="SearchButton"
                Style="{StaticResource Button_Style}" 
                Tag="OnlyPath"
                local:MyDependencyClass.DataForPath="{StaticResource Search}"
                Margin="10" />
    </WrapPanel>
</Window>

Code behind

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
    }
}

public class MyDependencyClass : DependencyObject
{
    #region IsCheckedOnDataProperty

    public static readonly DependencyProperty DataForPathProperty;

    public static void SetDataForPath(DependencyObject DepObject, string value)
    {
        DepObject.SetValue(DataForPathProperty, value);
    }

    public static string GetDataForPath(DependencyObject DepObject)
    {
        return (string)DepObject.GetValue(DataForPathProperty);
    }

    #endregion

    static MyDependencyClass()
    {
        PropertyMetadata MyPropertyMetadata = new PropertyMetadata(String.Empty);

        DataForPathProperty = DependencyProperty.RegisterAttached("DataForPath",
                                                            typeof(string),
                                                            typeof(MyDependencyClass),
                                                            MyPropertyMetadata);
    }
}

Note: In the Style I have not used TemplateBinding for attached property, because TemplateBinding doesn’t work outside a template or outside its VisualTree property, so you can’t even use TemplateBinding inside a template’s trigger. Therefore, we must use the construction {RelativeSource TemplatedParent} and a Path equal to the dependency property whose value you want to retrieve.

Output

To download the entire example please follow this link.