我在我的应用程序中使用 Telerik RadGridView，它有一个 GridViewSelectColumn 项目，它允许我选择网格中的各种项目。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。问题是我在 Caliburn.Micro 中使用了 MVVM 模式。是否需要在视图中找到控件并遍历选中项列表？对于一个简单的任务来说，这似乎需要做很多工作。我会很感激任何想法。
【问题讨论】：
标签： mvvm telerik selecteditem caliburn.micro radgridview
将布尔 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);
}
}
【讨论】：
有一种情况，你不能添加布尔值（例如 ObseravbleCollection。
请看this解决方案。
【讨论】：
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。
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
你可以使用这个行为：
// 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;
}
}
将此行为与 RadGridView 一起使用，如下所示：
<i:Interaction.Behaviors>
<behaviors:SelectedSyncBehavior SelectedItems="{Binding ViewModel.SelectedItems}" />
</i:Interaction.Behaviors>
【讨论】：
这是@Knasterbax 类的清理副本，带有显式私有修饰符和空传播：
// 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;
}
}
【讨论】：
这是上述答案的清理版本。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;
}
}
【讨论】：