如何强制ListBox重新加载ListBoxItems的属性 [英] How to force ListBox to reload properties of ListBoxItems

问题描述

有没有什么办法，如何强制ObservableCollection触发CollectionChanged？

我有一个ObservableCollection对象 ListBox item source，所以每当我添加/删除项目到集合中时，ListBox会相应的更改，但是当我更改集合中某些对象的属性时，ListBox仍会呈现旧值。

即使我修改一些属性，然后添加/删除对象到集合，没有任何反应，我仍然看到旧的值。

还有其他方法做这个？我发现接口INotifyPropertyChanged，但我不知道如何使用它。

解决方案

我同意Matt的评论。以下是一小段代码，以显示如何实现INotifyPropertyChanged。

===========

代码隐藏

===========

  using System; 
使用System.Collections.Generic; 
使用System.Linq; 
使用System.Text; 
使用System.Windows; 
使用System.Windows.Data; 
使用System.Windows.Documents; 
 
命名空间WpfApplication1 
 {
 ///< summary> 
 /// Window1.xaml的交互逻辑
 ///< / summary> 
 public partial class Window1：Window 
 {
昵称名称; 
 
 public Window1（）
 {
 InitializeComponent（）; 
 this.addButton.Click + = addButton_Click; 
 this.names = new Nicknames（）; 
 dockPanel.DataContext = this.names; 
} 
 
 void addButton_Click（object sender，RoutedEventArgs e）
 {
 this.names.Add（new Nickname（myName.Text，myNick.Text））; 
} 
} 
 public class昵称：System.Collections.ObjectModel.ObservableCollection< Nickname> {} 
 
 public class昵称：System.ComponentModel.INotifyPropertyChanged 
 {
 public event System.ComponentModel.PropertyChangedEventHandler PropertyChanged; 
 void Notify（string propName）
 {
 if（PropertyChanged！= null）
 {
 PropertyChanged（this，new System.ComponentModel.PropertyChangedEventArgs（propName））; 
} 
} 
 
 string name; 
 public string Name 
 {
 get {return name; } 
 set 
 {
 name = value; 
通知（名称）; 
} 
} 
 string nick; 
 public string Nick 
 {
 get {return nick; } 
 set 
 {
 nick = value; 
通知（Nick）; 
} 
} 
 public昵称（）：this（name，nick）{} 
 public昵称（字符串名称，字符串nick）
 {
 this.name = name; 
 this.nick = nick; 
} 
 
 public override string ToString（）
 {
 return Name.ToString（）++ Nick.ToString（）; 
} 
} 
} 
  

XAML

 < Window x：Class =WpfApplication1.Window1
 xmlns =http://schemas.microsoft.com / winfx / 2006 / xaml / presentation
 xmlns：x =http://schemas.microsoft.com/winfx/2006/xaml
 Title =Window1Height =300Width = 300> 
< Grid> 
< DockPanel x：Name =dockPanel> 
< TextBlock DockPanel.Dock =Top> 
< TextBlock VerticalAlignment =Center> Name：< / TextBlock> 
< TextBox Text ={Binding Path = Name}Name =myName/> 
< TextBlock VerticalAlignment =Center> Nick：< / TextBlock> 
< TextBox Text ={Binding Path = Nick}Name =myNick/> 
< / TextBlock> 
< Button DockPanel.Dock =Bottomx：Name =addButton>添加< / Button> 
< ListBox ItemsSource ={Binding}IsSynchronizedWithCurrentItem =True/> 
< / DockPanel> 
< / Grid> 
  

Is there any way, how to force ObservableCollection to fire CollectionChanged?

I have a ObservableCollection of objects ListBox item source, so every time I add/remove item to collection, ListBox changes accordingly, but when I change properties of some objects in collection, ListBox still renders the old values.

Even if I do modify some properties and then add/remove object to the collection, nothing happens, I still see old values.

Is there any other way around to do this? I found interface INotifyPropertyChanged, but I don't know how to use it.

解决方案

I agree with Matt's comments above. Here's a small piece of code to show how to implement the INotifyPropertyChanged.

===========
Code-behind
===========

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Data;
using System.Windows.Documents;

namespace WpfApplication1
{   
    /// <summary>
    /// Interaction logic for Window1.xaml
    /// </summary>
    public partial class Window1 : Window
    {
        Nicknames names;

        public Window1()
        {
            InitializeComponent();
            this.addButton.Click += addButton_Click;
            this.names = new Nicknames();
            dockPanel.DataContext = this.names;
        }

        void addButton_Click(object sender, RoutedEventArgs e)
        {
            this.names.Add(new Nickname(myName.Text, myNick.Text));
        }
}
public class Nicknames : System.Collections.ObjectModel.ObservableCollection<Nickname> { }

public class Nickname : System.ComponentModel.INotifyPropertyChanged
{
    public event System.ComponentModel.PropertyChangedEventHandler PropertyChanged;
    void Notify(string propName)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new System.ComponentModel.PropertyChangedEventArgs(propName));
        }
    }

    string name;
    public string Name
    {
        get { return name; }
        set
        {
            name = value;
            Notify("Name");
        }
    }
    string nick;
    public string Nick
    {
        get { return nick; }
        set
        {
            nick = value;
            Notify("Nick");
        }
    }
    public Nickname() : this("name", "nick") { }
    public Nickname(string name, string nick)
    {
        this.name = name;
        this.nick = nick;
    }

    public override string ToString()
    {
        return Name.ToString() + " " + Nick.ToString();
    }
  }
}

XAML

<Window x:Class="WpfApplication1.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window1" Height="300" Width="300">
<Grid>
    <DockPanel x:Name="dockPanel">
        <TextBlock DockPanel.Dock="Top">
        <TextBlock VerticalAlignment="Center">Name: </TextBlock>
        <TextBox Text="{Binding Path=Name}" Name="myName" />
        <TextBlock VerticalAlignment="Center">Nick: </TextBlock>
        <TextBox Text="{Binding Path=Nick}" Name="myNick" />
        </TextBlock>
        <Button DockPanel.Dock="Bottom" x:Name="addButton">Add</Button>
        <ListBox ItemsSource="{Binding}" IsSynchronizedWithCurrentItem="True" />
    </DockPanel>
</Grid>

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