Я использую Telerik RadGridView в своем приложении, и в нем есть элемент GridViewSelectColumn, который позволяет мне выбирать различные элементы в сетке. У меня есть кнопка, которая работает с этим выбором, но я не знаю, как получить список выбранных элементов. Проблема в том, что я использую шаблон MVVM с Caliburn.Micro. Нужно ли мне найти элемент управления в представлении и просмотреть список выбранных элементов? Кажется, что много работы для простой задачи. Буду признателен за любые идеи.
поиск выбранных элементов в Telerik RadGridView с использованием шаблона MVVM
Ответы (5)
Проблема с RadGridView от Telerik заключается в том, что его коллекция SelectedItem доступна только для чтения, поэтому вы не можете выполнить двустороннюю привязку к SelectedItems.
Обходным путем для этого является использование пользовательского поведения для синхронизации между RadGridView и вашей коллекцией SelectedItem ViewModels.
Вы можете использовать это поведение:
// 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;
}
}
Используйте это поведение с RadGridViews следующим образом:
<i:Interaction.Behaviors>
<behaviors:SelectedSyncBehavior SelectedItems="{Binding ViewModel.SelectedItems}" />
</i:Interaction.Behaviors>
Добавьте bool IsSelected к элементу в вашей коллекции:
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);
}
}
Вот очищенная копия класса @Knasterbax с явными приватными модификаторами и нулевым распространением:
// 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;
}
}
Вот очищенная версия ответа выше. Это удаляет символы подчеркивания, добавляет квалификаторы, аксессоры, фигурные скобки и т. д.
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;
}
}
Бывают ситуации, когда вы не можете добавить логическое значение (например, ObseravbleCollection.
Пожалуйста, взгляните на это решение.