我使用拖放将数据源对象(一个数据库模型)绑定到 DataGrid(基本上遵循 实体框架数据绑定与 WPF.
I used Drag and Drop to bind Data Source object (a DB model) to DataGrid (basically following this example in Entity Framework Databinding with WPF.
这个实现一切正常.
<Window.Resources> <CollectionViewSource x:Key="categoryViewSource" d:DesignSource="{d:DesignInstance {x:Type local:Category}, CreateList=True}"/> </Window.Resources> <Grid DataContext="{StaticResource categoryViewSource}"> ..背后的代码
private void Window_Loaded(object sender, RoutedEventArgs e) { System.Windows.Data.CollectionViewSource categoryViewSource = ((System.Windows.Data.CollectionViewSource)(this.FindResource("categoryViewSource"))); _context.Categories.Load(); categoryViewSource.Source = _context.Categories.Local; }视图模型
public MainWindow() { InitializeComponent(); this.DataContext = new MyViewModel(); }但是，当我尝试在 ViewModel 中使用相同的代码时，它不起作用(FindResource 不可用)，此外，我认为这不是正确的方法(即在 MVVM 中使用 x:Key).
However, when I try to use the same code from within ViewModel, it doesn‘t work (FindResource is not available), besides, I don’t think this is the right approach (i.e. to use x:Key in MVVM).
我真的很感谢任何帮助指出什么是使用 DataGrid 实现 CollectionViewSource 和 DataBinding 的正确方法.
I would really appreciate any help to point me what is the right way to implement CollectionViewSource and DataBinding with DataGrid.
推荐答案您有两个选项可以在 MVVM 中正确使用 CollectionViewSource -
You have two options to use CollectionViewSource properly with MVVM -
通过您的 ViewModel 公开项目的 ObservableCollection(在您的情况下为 Categories)并创建 CollectionViewSource 在像这样的 XAML 中 -
Expose an ObservableCollection of items (Categories in your case) through your ViewModel and create CollectionViewSource in XAML like this - <CollectionViewSource Source="{Binding Path=Categories}"> <CollectionViewSource.SortDescriptions> <scm:SortDescription PropertyName="CategoryName" /> </CollectionViewSource.SortDescriptions> </CollectionViewSource>
scm:xmlns:scm="clr-namespace:System.ComponentModel;assembly=Wind owsBase"
看到这个 - Filtering 使用 CollectionViewSource 的 XAML 集合
see this - Filtering collections from XAML using CollectionViewSource
直接从您的 ViewModel
看到这个 - 如何在 WPF 中导航、分组、排序和过滤数据
以下示例显示了如何创建集合视图和将其绑定到 ListBox
Following example shows how to create a collection view and bind it to a ListBox
查看 XAML:
<Window xmlns="schemas.microsoft/winfx/2006/xaml/presentation" xmlns:x="schemas.microsoft/winfx/2006/xaml" xmlns:scm="clr-namespace:System.ComponentModel;assembly=WindowsBase" x:Class="CustomerView"> <ListBox ItemsSource={Binding Customers} /> </Window>查看代码隐藏:
public class CustomerView : Window { public CustomerView() { DataContext = new CustomerViewModel(); } }视图模型:
public class CustomerViewModel { private readonly ICollectionView customerView; public ICollectionView Customers { get { return customerView; } } public CustomerViewModel() { IList<Customer> customers = GetCustomers(); customerView = CollectionViewSource.GetDefaultView( customers ); } }更新:
问.如果没有可排序的属性?例如如果有字符串或整数的 ObservableCollection?
Q. If there is no property to sort on? e.g. if there is an ObservableCollection of string or int?
A.在这种情况下，您可以简单地使用 . 作为属性名称:
A. In that case you can Simply use . as the property name:
<scm:SortDescription PropertyName="." />更多推荐
在 ViewModel 中使用 CollectionViewSource 的正确方法
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