編輯更改CollectionViewSource來源:我創建了一個新的VS2010 WPF appilication只有3個文件MainWindow.xaml,MainWindow.xaml.cs和MainWindowViewModel.cs(上市下面)。如果有人覺得真的有幫助,可以在幾秒鐘內重新創建問題(複製/粘貼)。當你運行應用程序時,DataGrid將顯示錯誤的字符串「OldCollection」。如果您將ItemsSource綁定更改爲MyCollection,則會顯示「NewCollection」,這是正確的。在MVVM世界
完整描述: 起初我有一個DataGrid,它的ItemsSource綁定到MyCollection。我有/需要一個方法UpdateCollection分配一個新的ObservableCollection <> MyCollection。隨着NotifyPropertyChange添加到MyCollection UI更新。
接下來有必要引入一個CollectionViewSource來啓用分組。通過綁定到MyCollectionView的UI,對UpdateCollection的調用現在不起作用。調試器確認MyCollectionView始終包含最初的MyCollection。我怎樣才能讓我的NewCollection被反映在視圖中?我試過View.Refresh(),綁定CollectionViewSource和其他無數的策略。
注意:其他人主要關心的是收集項目的更改,不更新視圖(分組/排序)而不調用刷新。我的問題是我正在爲CollectionViewSource分配一個全新的集合,並且視圖/ UI從不改變。
// 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; }
}
}
感謝,
這個問題讓我非常沮喪,我編輯了這個問題(請參閱編輯部分),以便任何人都可以在幾秒鐘內重現問題。根據你的建議,我添加了CollectionViewSource綁定到上面的代碼,但它沒有效果。 – aidesigner 2012-04-10 19:33:41