C# 在单独的类中收集的依赖项属性

我的问题与Silverlight有关（但我想WPF也是如此）

基本上，我知道如何在用户控件中创建依赖项属性以及如何使其工作。但我试图做的，但没有成功的是：在一个类中创建依赖属性（或多个），这个类将成为我的用户控件的依赖属性

换言之：

// my UserControl
public class DPTest : UserControl
{
    // dependency property, which type is a class, and this class will be holding other dependency properties        
    public static readonly DependencyProperty GroupProperty =
        DependencyProperty.Register("Group", typeof(DPGroup), typeof(DPTest), new PropertyMetadata(new DPGroup(), OnPropertyChanged));

    public DPGroup Group
    {
        get { return (DPGroup)GetValue(GroupProperty); }
        set { SetValue(GroupProperty, value); }
    }    

    // this occurs only when property Group will change, but not when a member of property Group will change        
    static void OnPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        DPTest g = d as DPTest;
        // etc.     
    }
}

// a class, where I want to hold my dependency properties
public class DPGroup : DependencyObject
{

    public static readonly DependencyProperty MyProperty1Property =
        DependencyProperty.RegisterAttached("MyProperty1", typeof(int), typeof(DPGroup), new PropertyMetadata(1, OnPropertyChanged));

    public int MyProperty1
    {
        get { return (int)GetValue(MyProperty1Property); }
        set { SetValue(MyProperty1Property, value); }
    }

    // I would like to notify "the parent" (which means user control "DPTest" ), that member MyProperty1 has changed
    static void OnPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        DPTest g = d as DPTest;
        if (g != null) g.textBox1.Text = g.Group.MyProperty1.ToString();
    }
}

我想要实现的是通知（在XAML的设计时）一个用户控件

DPTest

，组

属性（
Group.MyProperty1
）的成员更改了它的值。我设法在运行时实现了这一点，例如通过使用
DPGroup
类中定义的事件处理程序，但这在xaml的设计时不起作用

<Grid x:Name="LayoutRoot" Background="White">
    <local:DPTest>
        <local:DPTest.Group>
            <local:DPGroup MyProperty1="2"/>
        </local:DPTest.Group>
    </local:DPTest>
</Grid>

我看到一些类似于
UIElement.RenderTransform
（假设它是我的
组
属性）的东西，例如
ScaleTransform

<Grid x:Name="LayoutRoot" Background="White">
    <Grid.RenderTransform>
        <ScaleTransform ScaleX="0.4"/>
    </Grid.RenderTransform>      
</Grid>



ScaleX
类似于
MyProperty1
。不同之处在于，
ScaleX
（以XAML为单位）的值的变化将反映设计时的即时变化，而这正是我试图实现的

我试图在整个google/stack overflow和其他方面找到解决方案，但没有找到。到处都是在用户控件中创建依赖项属性的示例

谢谢你抽出时间。
非常感谢您的帮助

编辑：根据哈洛·伯吉斯的回答，a成功地在Silverlight中制作了一个工作示例。我将整个解决方案作为一个单独的答案放在下面。
来源：

依赖项属性或DependencyObject类不是本机的
支持INotifyPropertyChanged以生成通知
数据绑定的DependencyObject源属性值的更改数量
操作。有关如何创建要使用的属性的详细信息，请参见
在可以报告数据绑定目标更改的数据绑定中，请参见
数据绑定概述

如果设计一个系统，在任何子属性（任何子属性、任何子属性等）的任何属性发生更改时通知整个对象图，则效率低下。因此，当需要在属性更改时执行某些操作时，或者如果确实希望在任何子属性更改时收到通知，则应该使用数据绑定到特定属性，您应该实现INotifyPropertyChanged


例如：

public class DPGroup : DependencyObject, INotifyPropertyChanged 
{      
    public static readonly DependencyProperty MyProperty1Property =
        DependencyProperty.RegisterAttached(
        "MyProperty1",
        typeof(int),
        typeof(DPGroup),
        new PropertyMetadata(1));

    public int MyProperty1
    {        
        get { return (int)GetValue(MyProperty1Property); }        
        set { SetValue(MyProperty1Property, value); }
    } 

    protected override void OnPropertyChanged(DependencyPropertyChangedEventArgs e)
    {
        base.OnPropertyChanged(e);
        NotifyPropertyChanged(e.Property.Name);
    }

    public event PropertyChangedEventHandler PropertyChanged;
    protected void NotifyPropertyChanged(string propertyName)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

public class DPTest : UserControl   
{     
    public static readonly DependencyProperty GroupProperty =         
        DependencyProperty.Register(
        "Group",
        typeof(DPGroup),
        typeof(DPTest),
        new PropertyMetadata(
            new DPGroup(),
            new PropertyChangedCallback(OnGroupPropertyChanged)
            )
        );

    public DPGroup Group     
    {
        get { return (DPGroup)GetValue(GroupProperty); }
        set { SetValue(GroupProperty, value);}     
    }

    static void OnGroupPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        DPTest control = (DPTest)d;

        DPGroup oldGroup = e.OldValue as DPGroup;
        if (oldGroup != null)
        {
            oldGroup.PropertyChanged -=new PropertyChangedEventHandler(control.group_PropertyChanged);
        }

        DPGroup newGroup = e.NewValue as DPGroup;
        if (newGroup != null)
        {
            newGroup.PropertyChanged +=new PropertyChangedEventHandler(control.group_PropertyChanged);
        }

        control.UpdateTextBox();
    }

    private void group_PropertyChanged(object sender, PropertyChangedEventArgs e)
    {
        this.UpdateTextBox();
    }

    private void UpdateTextBox()
    {
        this.textBox1.Text = this.Group.MyProperty1.ToString(); 
    }

    private TextBox textBox1;

}  

好的，基于@Harlow Burgess answer，a成功地在Silverlight中制作了一个工作示例

基本上，区别在于，在SL中，
DependencyObject
类没有
OnPropertyChanged
方法，因此在
DPGroup
类中，我们不能覆盖它，但我们可以通过以下方式附加此方法：

new PropertyMetadata(1, OnPropertyChanged).

因此，
DPGroup
类将如下所示：

public class DPGroup : DependencyObject, INotifyPropertyChanged
{
    public static readonly DependencyProperty MyProperty1Property =
        DependencyProperty.RegisterAttached(
        "MyProperty1",
        typeof(int),
        typeof(DPGroup),
        new PropertyMetadata(1, OnPropertyChanged));

    public int MyProperty1
    {
        get { return (int)GetValue(MyProperty1Property); }
        set { SetValue(MyProperty1Property, value); }
    }   

    // static method invoked when MyProperty1 has changed value
    static void OnPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        DPGroup g = d as DPGroup;
        if (g != null)
        {
            g.MyProperty1 = (int)e.NewValue;
            // invoking event handler, to notify parent class about changed value of DP
            if (g.PropertyChanged != null) g.PropertyChanged(g, null);                
        }
    }

    // event handler, for use in parent class
    public event PropertyChangedEventHandler PropertyChanged;             
}

父类，包含类型为
DPGroup
的依赖属性：

public partial class DPTest : UserControl
{
    public static readonly DependencyProperty GroupProperty =
        DependencyProperty.Register(
        "Group",
        typeof(DPGroup),
        typeof(DPTest),
        new PropertyMetadata(
            new DPGroup(),
            new PropertyChangedCallback(OnGroupPropertyChanged)
            )
        );

    public DPGroup Group
    {
        get { return (DPGroup)GetValue(GroupProperty); }
        set { SetValue(GroupProperty, value); }
    }

    // static method invoked when Group property has changed value
    // here we need to attach event handler defined if DPGroup, so it will fire from inside Group property, 
    // when Group.MyProperty1 will change value
    static void OnGroupPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        DPTest control = (DPTest)d;

        DPGroup oldGroup = e.OldValue as DPGroup;
        // removing event handler from prevoius instance of DBGroup
        if (oldGroup != null)            
            oldGroup.PropertyChanged -= new PropertyChangedEventHandler(control.group_PropertyChanged);

        DPGroup newGroup = e.NewValue as DPGroup;
        // adding event handler to new instance of DBGroup
        if (newGroup != null)            
            newGroup.PropertyChanged += new PropertyChangedEventHandler(control.group_PropertyChanged);

        DPTest g = d as DPTest;
        if (g != null)
            control.UpdateTextBox();            
    }

    private void group_PropertyChanged(object sender, PropertyChangedEventArgs e)
    {
        UpdateTextBox();
    }

    // here you can do anything with changed value Group.MyProperty1
    private void UpdateTextBox()
    {
        this.textBox1.Text = this.Group.MyProperty1.ToString();
    }

    public DPTest()
    {
        InitializeComponent();

    }
}  

现在，
DPTest
的XAML部分：

<UserControl x:Class="Silverlight_Workbench_2.DPTest"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:local="clr-namespace:Silverlight_Workbench_2"
    mc:Ignorable="d"
    d:DesignHeight="300" d:DesignWidth="400" >

    <Grid x:Name="LayoutRoot" Background="White">

        <TextBox Height="23" HorizontalAlignment="Left" Margin="76,61,0,0" 
                 x:Name="textBox1" VerticalAlignment="Top" Width="120" />

    </Grid>
</UserControl>

就这些，再次感谢哈洛·伯吉斯的帮助
 感谢您的回答，但是在哪里实现INotifyPropertyChanged

？在用户控件

DPTest

或包含属性的类（

DPGroup

）上。我想，我尝试了第二种选择，但没有成功。谢谢你指出了一个效率低下的问题。我会给+1，但我还不能投票：）在DependencyObject上实现InotifyProperty更改。从UserControl订阅该通知。参见上面的示例代码。你不必投票，只要把它标记为答案，如果它对你有帮助的话。谢谢！尽管这段代码只在WPF中工作（做了一些修改），但我理解了一般的概念，并且能够在Silverlight中重现这段代码。为了能够在WPF中运行它，我需要a）从两个类中的DPs中删除

只读

，b）在我的环境中，我在XAML中实例化时出现异常

…

：无法将

组

属性的默认值绑定到特定线程。然后，我让DBGroup继承自

Freezable

（不是从DependencyObject继承的），就像这里写的那样：这就开始工作了。谢谢

public partial class DPTest : UserControl
{
    public static readonly DependencyProperty GroupProperty =
        DependencyProperty.Register(
        "Group",
        typeof(DPGroup),
        typeof(DPTest),
        new PropertyMetadata(
            new DPGroup(),
            new PropertyChangedCallback(OnGroupPropertyChanged)
            )
        );

    public DPGroup Group
    {
        get { return (DPGroup)GetValue(GroupProperty); }
        set { SetValue(GroupProperty, value); }
    }

    // static method invoked when Group property has changed value
    // here we need to attach event handler defined if DPGroup, so it will fire from inside Group property, 
    // when Group.MyProperty1 will change value
    static void OnGroupPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        DPTest control = (DPTest)d;

        DPGroup oldGroup = e.OldValue as DPGroup;
        // removing event handler from prevoius instance of DBGroup
        if (oldGroup != null)            
            oldGroup.PropertyChanged -= new PropertyChangedEventHandler(control.group_PropertyChanged);

        DPGroup newGroup = e.NewValue as DPGroup;
        // adding event handler to new instance of DBGroup
        if (newGroup != null)            
            newGroup.PropertyChanged += new PropertyChangedEventHandler(control.group_PropertyChanged);

        DPTest g = d as DPTest;
        if (g != null)
            control.UpdateTextBox();            
    }

    private void group_PropertyChanged(object sender, PropertyChangedEventArgs e)
    {
        UpdateTextBox();
    }

    // here you can do anything with changed value Group.MyProperty1
    private void UpdateTextBox()
    {
        this.textBox1.Text = this.Group.MyProperty1.ToString();
    }

    public DPTest()
    {
        InitializeComponent();

    }
}  

<UserControl x:Class="Silverlight_Workbench_2.DPTest"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:local="clr-namespace:Silverlight_Workbench_2"
    mc:Ignorable="d"
    d:DesignHeight="300" d:DesignWidth="400" >

    <Grid x:Name="LayoutRoot" Background="White">

        <TextBox Height="23" HorizontalAlignment="Left" Margin="76,61,0,0" 
                 x:Name="textBox1" VerticalAlignment="Top" Width="120" />

    </Grid>
</UserControl>

<UserControl x:Class="Silverlight_Workbench_2.DPTestMain"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:local="clr-namespace:Silverlight_Workbench_2"
    mc:Ignorable="d"
    d:DesignHeight="300" d:DesignWidth="400" xmlns:sdk="http://schemas.microsoft.com/winfx/2006/xaml/presentation/sdk">

    <Grid x:Name="LayoutRoot" Background="White">

        <local:DPTest>
            <local:DPTest.Group>
                <!--here we can change value, and it will be reflected in design window
                as a text in textBox1-->
                <local:DPGroup MyProperty1="8"/>
            </local:DPTest.Group>
        </local:DPTest>

    </Grid>
</UserControl>