[英]finding selected items in Telerik RadGridView using MVVM pattern
I am using a Telerik RadGridView in my application and it has a GridViewSelectColumn item in it, which allows me to select various items in the grid.我在我的应用程序中使用 Telerik RadGridView,它有一个 GridViewSelectColumn 项目,它允许我在网格中 select 各种项目。 I have a button that operates on this selection, but am not sure how to get the list of selected items.
我有一个操作此选择的按钮,但不确定如何获取所选项目的列表。 The problem is that I am using an MVVM pattern with Caliburn.Micro.
问题是我在 Caliburn.Micro 中使用了 MVVM 模式。 Do I need to find the control in the view and traverse the list of selected items?
是否需要在视图中找到控件并遍历选中项列表? That seems like a lot of work for a simple task.
对于一个简单的任务来说,这似乎需要做很多工作。 I would appreciate any ideas.
我会很感激任何想法。
The problem with Telerik's RadGridView is, that its SelectedItem collection is read-only, so you cannot bind two-way to SelectedItems. Telerik 的 RadGridView 的问题在于,它的 SelectedItem 集合是只读的,因此您不能将双向绑定到 SelectedItems。
A workaround for this is to use a custom Behavior to do the synchronization between RadGridView and your ViewModels SelectedItem collection解决方法是使用自定义行为在 RadGridView 和您的 ViewModels SelectedItem 集合之间进行同步
You may use this Behavior:您可以使用此行为:
// Behavior for synchronizing a RadDataGrid's SelectedItems collection with a SelectedItems collection of the ViewModel (the Network)
// The problem is, that RadDataGrid.SelectedItems is a read-only collection and therefore cannot be used for two-way binding.
class SelectedSyncBehavior
: Behavior<RadGridView>
{
bool _collectionChangedSuspended = false;
protected override void OnAttached()
{
base.OnAttached();
AssociatedObject.SelectedItems.CollectionChanged += GridSelectedItems_CollectionChanged;
}
/// <summary>
/// Getter/Setter for DependencyProperty, bound to the DataContext's SelectedItems ObservableCollection
/// </summary>
public INotifyCollectionChanged SelectedItems
{
get { return (INotifyCollectionChanged)GetValue(SelectedItemsProperty); }
set { SetValue(SelectedItemsProperty, value); }
}
/// <summary>
/// Dependency Property "SelectedItems" is target of binding to DataContext's SelectedItems
/// </summary>
public static readonly DependencyProperty SelectedItemsProperty =
DependencyProperty.Register("SelectedItems", typeof(INotifyCollectionChanged), typeof(SelectedSyncBehavior), new PropertyMetadata(OnSelectedItemsPropertyChanged));
/// <summary>
/// PropertyChanged handler for DependencyProperty "SelectedItems"
/// </summary>
private static void OnSelectedItemsPropertyChanged(DependencyObject target, DependencyPropertyChangedEventArgs args)
{
INotifyCollectionChanged collection = args.NewValue as INotifyCollectionChanged;
if (collection != null)
{
// Hook to the Network's SelectedItems
collection.CollectionChanged += (target as SelectedSyncBehavior).ContextSelectedItems_CollectionChanged;
}
}
/// <summary>
/// Will be called, when the Network's SelectedItems collection changes
/// </summary>
void ContextSelectedItems_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
if (_collectionChangedSuspended) return; // Don't react recursively to CollectionChanged events
_collectionChangedSuspended = true;
// Select and unselect items in the grid
if (e.NewItems != null)
foreach (object item in e.NewItems)
AssociatedObject.SelectedItems.Add(item);
if (e.OldItems != null)
foreach (object item in e.OldItems)
AssociatedObject.SelectedItems.Remove(item);
_collectionChangedSuspended = false;
}
/// <summary>
/// Will be called when the GridView's SelectedItems collection changes
/// </summary>
void GridSelectedItems_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
if (_collectionChangedSuspended) return; // Don't react recursively to CollectionChanged events
_collectionChangedSuspended = true;
// Select and unselect items in the DataContext
if (e.NewItems != null)
foreach (object item in e.NewItems)
(SelectedItems as IList).Add(item);
if (e.OldItems != null)
foreach (object item in e.OldItems)
(SelectedItems as IList).Remove(item);
_collectionChangedSuspended = false;
}
}
Use this Behavior with RadGridViews like this:将此行为与 RadGridViews 一起使用,如下所示:
<i:Interaction.Behaviors>
<behaviors:SelectedSyncBehavior SelectedItems="{Binding ViewModel.SelectedItems}" />
</i:Interaction.Behaviors>
Add a bool IsSelected to the item in your collection:将 bool IsSelected 添加到集合中的项目:
public class Customer
{
public int Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public bool IsSelected { get; set; }
}
private BindableCollection<Customer> _customers;
public BindableCollection<Customer> Customers
{
get { return _customers; }
set
{
_customers = value;
NotifyOfPropertyChange(() => Customers);
}
}
Here is a cleaned up copy of @Knasterbax's class with explicit private modifiers and null propagation:这是@Knasterbax 的 class 的清理副本,带有显式私有修饰符和 null 传播:
// Behavior for synchronizing Telerik RadDataGrid's SelectedItems collection
// with a SelectedItems collection of the ViewModel.
public class SelectedSyncBehavior : Behavior<RadGridView>
{
private bool collectionChangedSuspended;
public static readonly DependencyProperty SelectedItemsProperty = DependencyProperty.Register("SelectedItems",
typeof(INotifyCollectionChanged), typeof(SelectedSyncBehavior), new PropertyMetadata(OnSelectedItemsPropertyChanged));
protected override void OnAttached()
{
base.OnAttached();
AssociatedObject.SelectedItems.CollectionChanged += GridSelectedItems_CollectionChanged;
}
public INotifyCollectionChanged SelectedItems
{
get { return (INotifyCollectionChanged)GetValue(SelectedItemsProperty); }
set { SetValue(SelectedItemsProperty, value); }
}
private static void OnSelectedItemsPropertyChanged(DependencyObject target, DependencyPropertyChangedEventArgs args)
{
var collection = args.NewValue as INotifyCollectionChanged;
if (collection == null) return;
var selectedSyncBehavior = target as SelectedSyncBehavior;
if (selectedSyncBehavior != null) collection.CollectionChanged += selectedSyncBehavior.ContextSelectedItems_CollectionChanged;
}
private void ContextSelectedItems_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
if (collectionChangedSuspended) return; // Don't react recursively to CollectionChanged events
collectionChangedSuspended = true;
if (e.NewItems != null)
foreach (var item in e.NewItems)
AssociatedObject.SelectedItems.Add(item);
if (e.OldItems != null)
foreach (var item in e.OldItems)
AssociatedObject.SelectedItems.Remove(item);
collectionChangedSuspended = false;
}
private void GridSelectedItems_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
if (collectionChangedSuspended) return; // Don't react recursively to CollectionChanged events
collectionChangedSuspended = true;
if (e.NewItems != null)
foreach (var item in e.NewItems)
{
var list = SelectedItems as IList;
list?.Add(item);
}
if (e.OldItems != null)
foreach (var item in e.OldItems)
{
var list = SelectedItems as IList;
list?.Remove(item);
}
collectionChangedSuspended = false;
}
}
Here's a cleanup version of the answer above.这是上面答案的清理版本。 This removes underscores, adds qualifiers, accessors, braces, etc.
这将删除下划线、添加限定符、访问器、大括号等。
public class SelectedItemsBehavior : Behavior<RadGridView>
{
private bool collectionChangedSuspended;
/// <summary>
/// Called after the behavior is attached to an AssociatedObject.
/// </summary>
/// <remarks>
/// Override this to hook up functionality to the AssociatedObject.
/// </remarks>
protected override void OnAttached()
{
base.OnAttached();
this.AssociatedObject.SelectedItems.CollectionChanged += this.GridSelectedItemsCollectionChanged;
}
/// <summary>
/// Getter/Setter for DependencyProperty, bound to the DataContext's SelectedItems ObservableCollection
/// </summary>
public INotifyCollectionChanged SelectedItems
{
get => (INotifyCollectionChanged)this.GetValue(SelectedItemsProperty);
set => this.SetValue(SelectedItemsProperty, value);
}
/// <summary>
/// Dependency Property "SelectedItems" is target of binding to DataContext's SelectedItems
/// </summary>
public static readonly DependencyProperty SelectedItemsProperty =
DependencyProperty.Register("SelectedItems", typeof(INotifyCollectionChanged), typeof(SelectedItemsBehavior), new PropertyMetadata(OnSelectedItemsPropertyChanged));
/// <summary>
/// PropertyChanged handler for DependencyProperty "SelectedItems"
/// </summary>
private static void OnSelectedItemsPropertyChanged(DependencyObject target, DependencyPropertyChangedEventArgs args)
{
INotifyCollectionChanged collection = args.NewValue as INotifyCollectionChanged;
if (collection != null)
{
collection.CollectionChanged += ((SelectedItemsBehavior)target).ContextSelectedItemsCollectionChanged;
}
}
/// <summary>
/// Will be called, when the Network's SelectedItems collection changes
/// </summary>
private void ContextSelectedItemsCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
if (this.collectionChangedSuspended)
{
return;
}
this.collectionChangedSuspended = true;
if (e.NewItems != null)
{
foreach (object item in e.NewItems)
{
this.AssociatedObject.SelectedItems.Add(item);
}
}
if (e.OldItems != null)
{
foreach (object item in e.OldItems)
{
this.AssociatedObject.SelectedItems.Remove(item);
}
}
this.collectionChangedSuspended = false;
}
/// <summary>
/// Will be called when the GridView's SelectedItems collection changes
/// </summary>
private void GridSelectedItemsCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
if (this.collectionChangedSuspended)
{
return;
}
this.collectionChangedSuspended = true;
if (e.NewItems != null)
{
foreach (object item in e.NewItems)
{
((IList)this.SelectedItems).Add(item);
}
}
if (e.OldItems != null)
{
foreach (object item in e.OldItems)
{
((IList)this.SelectedItems).Remove(item);
}
}
this.collectionChangedSuspended = false;
}
}
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.