MultiBinding与MultiValueConverter不更新 [英] MultiBinding with MultiValueConverter does not update

问题描述

场景：

我有一个带有两个日期检视器和一个列表视图的窗口。
listliew包含一些称为条目的数据绑定元素。一个条目有一个名为date的属性。

我只想让我的列表显示日期在我的两个datepickes日期之间的条目。

我将用于将列表视图绑定到条目和日期的xaml代码：

 < ListView.ItemsSource> ; 
< MultiBinding Converter ={StaticResource EntriesFilterConv}
 UpdateSourceTrigger =PropertyChanged> 
< Binding Path =EntriesUpdateSourceTrigger =PropertyChanged/> 
< Binding ElementName =EntryFromDatePath =SelectedDate
 UpdateSourceTrigger =PropertyChanged/> 
< Binding ElementName =EntryToDatePath =SelectedDate
 UpdateSourceTrigger =PropertyChanged/> 
< / MultiBinding> 
< /ListView.ItemsSource> 
  

但是，这不工作。当一个SelectedDate更改时，我的转换器被调用，但是当Entries发生变化时，它不会被调用。

正常的数据绑定如下：

 < ListView ItemsSource ={Binding Entries}> 
 ... 
< / ListView> 
  

列表视图正常更新。
任何想法？

解决方案

我认为以下可能是这样的：如果你直接绑定到 Entries ListView将收听 CollectionChanged 事件，但如果这样的绑定在 MultiBinding 唯一可能导致重新评估的事情可能是一个 PropertyChanged 通知，这可能不适用于模型中的Entries属性。

也许您可以订阅收藏的 CollectionChanged 事件，并提出一个 PropertyChanged 事件或在 MultiBinding 中获取 BindingExpression 以手动调用更新。

it seems that I have a problem with my multibinding.

Scenario:
I have a window with two datepickers and a listview. The listliew contains some data bound elements called "entries". An entry has a property called "date".

I just want my listview to show entries whose date is in between my two datepickes dates.

My xaml code for binding the listview to the entries and dates:

<ListView.ItemsSource>
  <MultiBinding Converter="{StaticResource EntriesFilterConv}"
                UpdateSourceTrigger="PropertyChanged">
    <Binding Path="Entries" UpdateSourceTrigger="PropertyChanged"/>
    <Binding ElementName="EntryFromDate" Path="SelectedDate"
             UpdateSourceTrigger="PropertyChanged"/>
    <Binding ElementName="EntryToDate" Path="SelectedDate"
             UpdateSourceTrigger="PropertyChanged"/>
  </MultiBinding>
</ListView.ItemsSource>

However, this doesnt work. My converter is called when a SelectedDate changes but its never called when Entries changes.

With normal data binding like this:

<ListView ItemsSource="{Binding Entries}">
  ...
</ListView>

The listview updates normally. Any idea?

解决方案

I think the following might cause this: If you bind directly to the Entries the ListView will listen to CollectionChanged events, but if such a binding is inside a MultiBinding the only thing that would cause a reevaluation could be a PropertyChanged notification, which might not exist for the Entries property in your model.

Maybe you can subscribe to the CollectionChanged event of your collection and raise a PropertyChanged event or get the BindingExpression within your MultiBinding to call an update manually.

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