如何通过MVVM为DataGrid ItemSource设置过滤器 [英] How to set a filter for a DataGrid ItemSource via MVVM

问题描述

我有一个 DataGrid 绑定到XAML中的CollectionViewSource 。

I have a DataGrid bound to a CollectionViewSource in XAML.

<Window.Resources>
  <local:MainWindowViewModel x:Key="ViewModel"/>
  <CollectionViewSource x:Key="cvsEntries" 
                        Source="{Binding LogEntriesStore, 
                                 Source={StaticResource ViewModel}}"/>
</Window.Resources>

LogEntriesStore 是一个 ObservableCollection 是一个DTO，在本次讨论中并不重要）

LogEntriesStore is an ObservableCollection (LogEntry is a DTO that's not important in this discussion)

将DataGrid 声明为：

The DataGrid is declared as:

<DataGrid AutoGenerateColumns="False" 
          Margin="0" 
          Name="dataGrid1" 
          ItemsSource="{Binding Source={StaticResource cvsEntries}}" 
          IsReadOnly="True">

现在我在这个 DataGrid 中的各种单元格上有上下文菜单，关闭过滤请求。右键单击一个单元格，然后选择过滤器以过滤所有行，并显示此特定值。

Now I have context menus on various cells in this DataGrid, to kick off a request for filtering. Right click on a cell, and pick filter to filter all the rows, and show only this particular value.

MVVM获取过滤请求，但现在是棘手的位。如何在CollectionViewSource上设置过滤器？

The MVVM gets the request to filter, but the now the tricky bit. How do I set the filter on the CollectionViewSource?

（除此之外 - 这将是一个在公园里散步的Silverlight PagedCollectionView 但是在WPF中似乎不可用，是吗？）

(as an aside -- this would have been a walk in the park with a Silverlight PagedCollectionView but that doesn't seem to be available in WPF, is that right?)

推荐答案

简单。您只需在视图模型中移动集合视图：

Very simple. You just need to move the collection view inside the view model:

1. 在 MainWindowViewModel 定义一个类型为 ICollectionView 的属性：

1. In MainWindowViewModel define a property of type ICollectionView:

public ICollectionView LogEntriesStoreView { get; private set; }

刚刚初始化了 LogEntriesStore 属性，您需要使用以下代码初始化 LogEntriesStoreView 属性：

Right after you have initialized the LogEntriesStore property, you need to initialize the LogEntriesStoreView property with the following code:

LogEntriesStoreView = CollectionViewSource.GetDefaultView(LogEntriesStore);

然后，您需要删除 CollectionViewSource 从XAML修改 ItemsSource 绑定到指向新创建的集合视图属性：

Then you need to remove the CollectionViewSource from XAML and modify the ItemsSource binding to point to the newly created collection view property:

<DataGrid AutoGenerateColumns="False" 
          Margin="0" 
          Name="dataGrid1" 
          ItemsSource="{Binding LogEntriesStoreView, Source={StaticResource ViewModel}}" 
          IsReadOnly="True">

就是这样。现在，您可以访问视图模型中的集合视图，您可以在其中修改过滤器。

That's it. Now you have the access to the collection view inside your view model, where you can modify the filter.

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