详细描述：
起初我有一个DataGrid,其ItemsSource绑定到MyCollection.我需要一个方法UpdateCollection来分配一个新的ObservableCollection<>到MyCollection.通过向MyCollection添加NotifyPropertyChange,UI更新.
接下来,有必要引入一个CollectionViewSource来启用分组.将UI绑定到MyCollectionView后,对UpdateCollection的调用现在无效.调试器确认MyCollectionView始终包含初始MyCollection.如何让我的NewCollection反映在View中？我尝试过View.Refresh(),绑定CollectionViewSource,以及无数其他策略.
注意：主要是其他人关注收集项目的更改而不更新视图(分组/排序)而不调用Refresh.我的问题是我正在为CollectionViewSource分配一个全新的集合,并且视图/ UI永远不会改变.
// MainWindow.xaml
<Window x:Class="CollectionView.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<Grid>
<DataGrid Name="grid" ItemsSource="{Binding MyCollectionView}" />
</Grid>
</Window>
//MainWindow.xaml.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows;
namespace CollectionView
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
DataContext = new MainWindowViewModel();
}
}
}
//MainWindowViewModel.cs:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Collections.ObjectModel;
using System.Windows.Data;
using System.ComponentModel;
namespace CollectionView
{
class MainWindowViewModel : INotifyPropertyChanged
{
public MainWindowViewModel()
{
MyCollection = new ObservableCollection<MyObject>() { new MyObject() { TestString = "OldCollection" } };
MyCollectionViewSource = new CollectionViewSource();
// Bind CollectionViewSource.Source to MyCollection
Binding MyBind = new Binding() { Source = MyCollection };
BindingOperations.SetBinding(MyCollectionViewSource,CollectionViewSource.SourceProperty,MyBind);
// The DataGrid is bound to this ICollectionView
MyCollectionView = MyCollectionViewSource.View;
// This assignment here to demonstrate that View/UI does not update to show "NewCollection"
MyCollection = new ObservableCollection<MyObject>() { new MyObject() { TestString = "NewCollection" } };
}
// Collection Property
// NotifyPropertyChanged added specifically to notify of MyCollection re-assignment
ObservableCollection<MyObject> _MyCollection;
public ObservableCollection<MyObject> MyCollection
{
get { return _MyCollection; }
set
{
if (value != _MyCollection)
{
_MyCollection = value;
NotifyPropertyChanged("MyCollection");
}
}
}
public CollectionViewSource MyCollectionViewSource { get; private set; }
public ICollectionView MyCollectionView { get; private set; }
// Method updates MyCollection itself (Called via ICommand from another ViewModel)
public void UpdateCollection(ObservableCollection<MyObject> NewCollection)
{
MyCollection = NewCollection;
}
public event PropertyChangedEventHandler PropertyChanged;
private void NotifyPropertyChanged(String info)
{
if (PropertyChanged != null)
{
PropertyChanged(this,new PropertyChangedEventArgs(info));
}
}
}
class MyObject
{
public string TestString { get; set; }
}
}
谢谢,
解决方法
首先,您可以使用ObservableCollection并创建一次ICollectionView(分组,排序).您可以使用.Clear()并添加新Collection中的项目,而不是替换ObservableCollection.这还有一个额外的好处,就是不会破坏你的分组和排序.
第二种方法：无论何时替换ObservableCollection,都必须创建一个新的ICollectionView进行排序和分组.
this._view = (ICollectionView)CollectionViewSource.GetDefaultView(this.MyCollection);
如果使用DefaultView,只需绑定到您的集合即可
<DataGrid Name="grid" ItemsSource="{Binding MyCollection}" />
你可以扔掉你的CollectionViewSource代码绑定的东西.
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