自定义控件绑定属性

Question

I have created a custom control but I can't bind a property to the content like this :

<Style TargetType="control:Pie">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="control:Pie">
                    <Border
                        Background="{TemplateBinding Background}"
                        BorderBrush="{TemplateBinding BorderBrush}"
                        BorderThickness="{TemplateBinding BorderThickness}">

                        <ContentControl Content="{Binding Path=Test}"/>
                    </Border>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

And in my control

public string Test
    {
        get { return (string)GetValue(TestProperty); }
        set { SetValue(TestProperty, value); }
    }
    public static readonly DependencyProperty TestProperty =
        DependencyProperty.Register(
            "Test",
            typeof(string),
            typeof(Pie),
            new PropertyMetadata(null));

When I create the control a set a string in the Test property but nothing appears in the view...

Answer 1

TemplateBinding is used to bind to the templated control and therefore only works in ControlTemplate . Just 2 Lines above you already used TemplateBinding for Background, BorderBrush and BorderThickness.

Binding on the otherhand binds to the DataContext , which is an object used to take "business" related data from the user. It should be independant of how your controls works and

As a rule of thumb: If you use a normal binding in a ControlTemplate , which doesn't have a RelativeSource , ElementName or Source set, it usually should not appear in a ControlTemplate or Style.