WPF绑定不通知更改 [英] WPF binding not notifying of changes

问题描述

我有一个WPF排序/绑定问题。 （免责声明：我非常新的WPF和数据绑定，所以道歉，如果我问一个非常愚蠢的问题： - ））

首先，我有一个linqToSql实体类联系人与 EntitySet< Booking> 财产预订。

如果我直接将此Bookings属性绑定到一个 ListView ，应用程序似乎正确地通知了 ListView ，使得




$ b

  //此代码工作，但是预订未排序
 var binding = new Binding（）; 
 binding.Source = contact.Bookings; 
 reservations.SetBinding（ItemsControl.ItemsSourceProperty，binding）; 
  

但是，我似乎无法找到一种排序EntitySet的方法（见这篇文章），我试图绑定到一个Observable集合，例如：

  //此代码不会通知ListView中所选项目的更改
 var binding = new Binding ）; 
 binding.Source = new ObservableCollection< Booking>（contact.Bookings.OrderByDescending（b => b.T​​ravelDate）.ToList（））; 
 reservations.SetBinding（ItemsControl.ItemsSourceProperty，binding）; 
  

但是，这似乎没有正确通知评论文本框，以便更新。

如果任何人有一个解决方案，在其绑定之前或之后对数据进行排序，或者其他解决方案将非常感谢。

解决方案

你应该绑定到一个 CollectionView ，而不是集合本身。这将允许您指定所需的任何排序条件。示例：

  var collectionView = new ListCollectionView（contact.Bookings）; 
 collectionView.SortDescriptions.Add（new SortDescription（TravelDate，ListSortDirection.Ascending））; 
 var binding = new Binding（）; 
 binding.Source = collectionView; 
 reservations.SetBinding（ItemsControl.ItemsSourceProperty，binding）; 
  

I have a WPF sorting/binding issue. (Disclaimer: I am very new to WPF and databinding so apologise if I am asking a really dumb question :-))

Firstly, I have a linqToSql entity class Contact with an EntitySet<Booking> property Bookings on it.

If I directly bind this Bookings property to a ListView, the application seems to correctly notify of changes to the selected item in the ListView, such that a textbox with {Binding Path=Bookings/Comments} updates correctly.

// This code works, but Bookings is unsorted  
var binding = new Binding();
binding.Source = contact.Bookings;
bookings.SetBinding(ItemsControl.ItemsSourceProperty, binding);

However, as I can't seem to be able to find a way to sort an EntitySet (see this post), I am trying to bind instead to an Observable collection, e.g:

// This code doesn't notify of selected item changes in the ListView
var binding = new Binding();
binding.Source = new ObservableCollection<Booking>(contact.Bookings.OrderByDescending(b => b.TravelDate).ToList());
bookings.SetBinding(ItemsControl.ItemsSourceProperty, binding);

But this doesn't seem to notify the comments textbox correctly such that it updates.

If anyone has a solution for either sorting the data before or after its bound, or another solution that will work that would be much appreciated.

解决方案

You should bind to a CollectionView rather than the collection itself. That will allow you to specify whatever sorting criteria you require. Example:

var collectionView = new ListCollectionView(contact.Bookings);
collectionView.SortDescriptions.Add(new SortDescription("TravelDate", ListSortDirection.Ascending));
var binding = new Binding();
binding.Source = collectionView;
bookings.SetBinding(ItemsControl.ItemsSourceProperty, binding);

这篇关于WPF绑定不通知更改的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！