wpf 纯粹在 XAML 中对组合框进行排序
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原文地址: http://stackoverflow.com/questions/2274690/
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Sorting a combobox purely in XAML
提问by Dave
I'm surprised that no one has asked this before here... well, at least I haven't found an answer here or anywhere else, actually.
我很惊讶之前没有人在这里问过这个问题……好吧，实际上，至少我在这里或其他任何地方都没有找到答案。
I have a ComboBox that is databound to an ObservableCollection. Everything worked great until the guys wanted the contents sorted. No problem -- I end up changing the simple property out:
我有一个数据绑定到 ObservableCollection 的 ComboBox。一切都很好，直到这些人想要对内容进行排序。没问题——我最终改变了简单的属性：
public ObservableCollection<string> CandyNames { get; set; } // instantiated in constructor
for something like this:
对于这样的事情：
private ObservableCollection<string> _candy_names; // instantiated in constructor
public ObservableCollection<string> CandyNames
{
get {
_candy_names = new ObservableCollection<string>(_candy_names.OrderBy( i => i));
return _candy_names;
}
set {
_candy_names = value;
}
}
This post is really two questions in one:
这篇文章实际上是两个问题合二为一：
- How can I sort a simple ComboBox of strings in XAML only. I have researched this and can only find info about a SortDescription class, and this is the closest implementation I could find, but it wasn't for a ComboBox.
- Once I implemented the sorting in code-behind, it my databinding was broken; when I added new items to the ObservableCollection, the ComboBox items didn't update! I don't see how that happened, because I didn't assign a name to my ComboBox and manipulate it directly, which is what typically breaks the binding.
- 如何仅在 XAML 中对简单的字符串 ComboBox 进行排序。我对此进行了研究，只能找到有关 SortDescription 类的信息，这是我能找到的最接近的实现，但它不适用于 ComboBox。
- 一旦我在代码隐藏中实现了排序，我的数据绑定就被破坏了；当我向 ObservableCollection 添加新项目时，ComboBox 项目没有更新！我不明白这是怎么发生的，因为我没有为我的 ComboBox 分配名称并直接操作它，这通常会破坏绑定。
Thanks for your help!
谢谢你的帮助！
采纳答案by Wallstreet Programmer
You can use a CollectionViewSource to do the sorting in XAML, however you need to refresh it's view if the underlying collection changes.
您可以使用 CollectionViewSource 在 XAML 中进行排序，但是如果基础集合发生更改，您需要刷新它的视图。
XAML:
XAML：
<Window x:Class="CBSortTest.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:scm="clr-namespace:System.ComponentModel;assembly=WindowsBase"
Height="300" Width="300">
<Window.Resources>
<CollectionViewSource Source="{Binding Path=CandyNames}" x:Key="cvs">
<CollectionViewSource.SortDescriptions>
<scm:SortDescription />
</CollectionViewSource.SortDescriptions>
</CollectionViewSource>
</Window.Resources>
<StackPanel>
<ComboBox ItemsSource="{Binding Source={StaticResource cvs}}" />
<Button Content="Add" Click="OnAdd" />
</StackPanel>
</Window>
Code behind:
后面的代码：
using System;
using System.Collections.ObjectModel;
using System.Windows;
using System.Windows.Data;
namespace CBSortTest
{
public partial class Window1 : Window
{
public Window1()
{
InitializeComponent();
CandyNames = new ObservableCollection<string>();
OnAdd(this, null);
OnAdd(this, null);
OnAdd(this, null);
OnAdd(this, null);
DataContext = this;
CandyNames.CollectionChanged +=
(sender, e) =>
{
CollectionViewSource viewSource =
FindResource("cvs") as CollectionViewSource;
viewSource.View.Refresh();
};
}
public ObservableCollection<string> CandyNames { get; set; }
private void OnAdd(object sender, RoutedEventArgs e)
{
CandyNames.Add("Candy " + _random.Next(100));
}
private Random _random = new Random();
}
}
