Question

我的项目中有一个自定义ItemsControl，我正在尝试为它编写一个样式，它将静态项目列表与控件本身的依赖项属性上的项目列表相结合。 / p>

以下是我的资源词典中的相应XAML：

<x:Array Type="{x:Type System:Object}" x:Key="Static_CloudItems">
    <Button>One</Button>
    <Button>Two</Button>
    <Button>Three</Button>
</x:Array>

<Style TargetType="{x:Type ControlsBase:CloudControl}" x:Key="BasicCloudStyle">
    <Setter Property="ItemsSource">
        <Setter.Value>
            <CompositeCollection>
                <CollectionContainer Collection="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ControlsBase:CloudControl}}, Path=CloudItems}" />
                <CollectionContainer Collection="{StaticResource Static_CloudItems}" />
            </CompositeCollection>
        </Setter.Value>
    </Setter>
</Style>

然后我的控件/窗口/中的相应代码：

<ControlsBase:CloudControl Style="{DynamicResource BasicCloudStyle}">
    <ControlsBase:CloudControl.CloudItems>
        <x:Array Type="{x:Type System:Object}">
            <Button>Four</Button>
            <Button>Five</Button>
        </x:Array>
    </ControlsBase:CloudControl.CloudItems>
</ControlsBase:CloudControl>

理念是样式应该将静态元素与控件的每个实例版本上定义的任何元素组合在一起。

我的问题是，上面的绑定不起作用（我也意识到了原因！）所以我需要一种能够绑定到样式父级的方法，但因为setter不在visual / logical中树，只是一个属性我有点困惑如何继续。

Answer 1

如何实现在幕后为Control构建正确的CompositeCollection的IValueConverter？见下面的示例：

XAML：

<Window x:Class="StackOverflow.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:System="clr-namespace:System;assembly=mscorlib"
        xmlns:local="clr-namespace:StackOverflow"
        Title="MainWindow" Height="350" Width="525"
        x:Name="window">
    <Window.Resources>
        <x:Array Type="{x:Type System:Object}" x:Key="Static_CloudItems">
            <Button>One</Button>
            <Button>Two</Button>
            <Button>Three</Button>
        </x:Array>

        <local:MyItemsSourceConverter x:Key="myConverter"/>
        <Style TargetType="{x:Type local:MyControl}" x:Key="BasicCloudStyle">
            <Setter Property="ItemsSource" 
                    Value="{Binding RelativeSource={RelativeSource Self}, Converter={StaticResource myConverter}}"/>
        </Style>
    </Window.Resources>

    <local:MyControl Style="{StaticResource BasicCloudStyle}" >
        <local:MyControl.InstanceItems>
            <System:String>Item1</System:String>
            <System:String>Item2</System:String>
            <System:String>Item3</System:String>
        </local:MyControl.InstanceItems>
    </local:MyControl>
</Window>

代码隐藏：

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

public class MyControl : ListBox 
{
    public ObservableCollection<object> InstanceItems
    {
        get { return (ObservableCollection<object>)GetValue(InstanceItemsProperty); }
        set { SetValue(InstanceItemsProperty, value); }
    }

    // Using a DependencyProperty as the backing store for InstanceItems.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty InstanceItemsProperty =
        DependencyProperty.Register("InstanceItems", typeof(ObservableCollection<object>), 
        typeof(MyControl), new UIPropertyMetadata(new ObservableCollection<object>()));
}

public class MyItemsSourceConverter : IValueConverter
{
    #region IValueConverter Members

    public object Convert(object value, System.Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        MyControl mc = value as MyControl;
        if (mc != null)
        {
            CompositeCollection cc = new CompositeCollection();

            CollectionContainer container1 = new CollectionContainer();
            BindingOperations.SetBinding(container1, CollectionContainer.CollectionProperty,
                new Binding()
                {
                    Source = mc,
                    Path = new PropertyPath("InstanceItems")
                });
            cc.Add(container1);

            CollectionContainer container2 = new CollectionContainer()
            {
                Collection = mc.FindResource("Static_CloudItems") as Array
            };

            cc.Add(container2);

            return cc;
        }
        return null;
    }

    public object ConvertBack(object value, System.Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new System.NotImplementedException();
    }

    #endregion
}

绑定范围 - 样式和范围模板

1 个答案: