多个用户控件共享集合依赖项属性 [英] Multiple user controls share collection dependency property

问题描述

我已经基于列表框实现了自己的用户控件。它具有带有集合类型的依赖项属性。当我在一个窗口中只有一个usercontrol实例时，它可以正常工作，但是如果有多个实例，我会感到它们共享集合依赖项属性的问题。下面是说明此情况的示例。

I have implemented my own usercontrol based on listboxes. It has a dependency property with type of a collection. It works fine when I have only one instance of the usercontrol in a window, but if I have multiple instances I get problem that they share the collection dependency property. Below is a sample illustrating this.

我的用户控件名为SimpleList：

My user control called SimpleList:

<UserControl x:Class="ItemsTest.SimpleList"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Name="_simpleList">
    <StackPanel>
        <TextBlock Text="{Binding Path=Title, ElementName=_simpleList}" />
        <ListBox 
            ItemsSource="{Binding Path=Numbers, ElementName=_simpleList}">
            <ListBox.ItemsPanel>
                <ItemsPanelTemplate>
                    <StackPanel Orientation="Horizontal" />
                </ItemsPanelTemplate>
            </ListBox.ItemsPanel>
        </ListBox>
    </StackPanel>    
</UserControl>

后面的代码：

using System.Collections.Generic;
using System.Windows;
using System.Windows.Controls;

namespace ItemsTest
{
    public partial class SimpleList : UserControl
    {
        public SimpleList()
        {
            InitializeComponent();
        }

        public string Title
        {
            get { return (string)GetValue(TitleProperty); }
            set { SetValue(TitleProperty, value); }
        }

        public static readonly DependencyProperty TitleProperty =
            DependencyProperty.Register("Title", typeof(string), typeof(SimpleList), new UIPropertyMetadata(""));


        public List<int> Numbers 
        {
            get { return (List<int> )GetValue(NumbersProperty); }
            set { SetValue(NumbersProperty, value); }
        }

        public static readonly DependencyProperty NumbersProperty =
            DependencyProperty.Register("Numbers ", typeof(List<int>), typeof(SimpleList), new UIPropertyMetadata(new List<int>()));
    }
}

我这样使用：

   <StackPanel>
        <ItemsTest:SimpleList Title="First">
            <ItemsTest:SimpleList.Numbers>
                <sys:Int32>1</sys:Int32>
                <sys:Int32>2</sys:Int32>
                <sys:Int32>3</sys:Int32>
            </ItemsTest:SimpleList.Numbers>
        </ItemsTest:SimpleList>
        <ItemsTest:SimpleList Title="Second">
            <ItemsTest:SimpleList.Numbers>
                <sys:Int32>4</sys:Int32>
                <sys:Int32>5</sys:Int32>
                <sys:Int32>6</sys:Int32>
            </ItemsTest:SimpleList.Numbers>
        </ItemsTest:SimpleList>
    </StackPanel>

我希望以下内容出现在我的窗口中：

I expect the following to show up in my window:

First
123
Second
456

但是我看到的是：

First
123456
Second
123456

如何获取多个SimpleList而不共享其Numbers集合？ / p>

How do I get multiple SimpleList not to share their Numbers Collection???

推荐答案

找到答案了，构造函数需要初始化属性而不是让静态属性自己做

Found the answer, the constructor needs to initialize the property instead of letting the static property do itself:

public SimpleList()
{
   SetValue(NumbersProperty, new List<int>()); 

   InitializeComponent();
}

集合类型依赖项属性

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