如何公开样式的内部控制？

Question

问题似乎很简单： 我有一个UserControl，我的控件包含一个Button。

Button 元素可以设置样式。但我不想在我的控制中拥有样式定义。我的控件甚至没有 XAML。我想在 XAML 中设置这样的样式：

<Style TargetType="local:MyControl">
    <Setter Property="ItsButton.Padding" Value="8" />
</Style>

这样不行。它是如何工作的？ 我知道我可以将任何内部控件的属性绑定到我的 UserControl 依赖属性，它会起作用。但是绑定很多属性有点矫枉过正，做简单的事情真的需要这么多的编码，还是更容易/更快/更简单的方法？

顺便说一句，这对你来说看起来并不过分，想象一下我有很多内部控件，比如按钮，比如说InputBoxes 等等。

这是示例控制代码：

class Installable : UserControl {

    public static readonly DependencyProperty ValueProperty = DependencyProperty.Register(
        "Value",
        typeof(object),
        typeof(Installable),
        new FrameworkPropertyMetadata(OnValueChanged));

    public static readonly DependencyProperty InstallButtonProperty = DependencyProperty.Register(
        "InstallButton",
        typeof(Button),
        typeof(Installable),
        new FrameworkPropertyMetadata(null, FrameworkPropertyMetadataOptions.None));

    public static readonly DependencyProperty InstallTextProperty = DependencyProperty.Register(
        "InstallText",
        typeof(string),
        typeof(Installable),
        new FrameworkPropertyMetadata(OnInstallTextChanged));

    public static readonly DependencyProperty CommandProperty = DependencyProperty.Register(
        "Command",
        typeof(ICommand),
        typeof(Installable),
        new FrameworkPropertyMetadata(OnCommandChanged));

    public static readonly DependencyProperty CommandParameterProperty = DependencyProperty.Register(
        "CommandParameter",
        typeof(object),
        typeof(Installable),
        new FrameworkPropertyMetadata(OnCommandParameterChanged));

    public object Value {
        get => GetValue(ValueProperty);
        set => SetValue(ValueProperty, value);
    }

    public Button InstallButton {
        get => (Button)GetValue(InstallButtonProperty);
        set => SetValue(InstallButtonProperty, value);
    }

    public string InstallText {
        get => (string)GetValue(InstallTextProperty);
        set => SetValue(InstallTextProperty, value);
    }

    public ICommand Command {
        get => (ICommand)GetValue(CommandProperty);
        set => SetValue(CommandProperty, value);
    }

    public object CommandParameter {
        get => GetValue(CommandParameterProperty);
        set => SetValue(CommandParameterProperty, value);
    }


    public Installable() {
        InstallButton = new Button();
        Content = Value ?? InstallButton;
        InstallText = "Install";
    }

    private static void OnValueChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) {
        var control = d as Installable;
        var value = e.NewValue;
        control.Content = value ?? control.InstallButton;
    }

    private static void OnInstallTextChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) {
        var control = d as Installable;
        var text = e.NewValue as string;
        control.InstallButton.Content = text;
    }


    private static void OnCommandChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) {
        var control = d as Installable;
        var command = e.NewValue as ICommand;
        control.InstallButton.Command = command;
    }

    private static void OnCommandParameterChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) {
        var control = d as Installable;
        var value = e.NewValue;
        control.InstallButton.CommandParameter = value;
    }

}

控件在不为空时显示其Value，否则为InstallButton。 就像如果值未设置 - 它包含按钮，当值设置时 - 包含值。该控件的作用就像魅力一样，但是当我在MainWindow XAML 中设置Button 样式时，它不会影响我的UserControl 中的按钮。

也许我的Button 可以以某种方式继承Button 在MainWindow XAML 中定义的样式？

Answer 1

控件样式可以在其资源中定义一个默认按钮样式，该样式将自动应用于控件的所有按钮子元素。

<Style TargetType="local:MyControl">
    <Style.Resources>
        <Style TargetType="Button">
            <Setter Property="Margin" Value="8"/>
        </Style>
    </Style.Resources>
</Style>