如何重写 WPF ItemsControl 中预定义依赖项 属性 ItemsSource 的 属性ChangedCallback
How to Override PropertyChangedCallback of a predefined Dependency Property ItemsSource in a WPF ItemsControl
如何覆盖 PropertyChangedCallback
预定义的依赖关系 属性 ItemsSource
在 WPF ItemsControl
.
我开发了一个继承自ItemsControl
的WPF自定义控件。因为我使用了预定义的依赖关系 属性 ItemsSource
。因为我需要在 Collection
更新后监控和检查数据。
我在google中搜索了很多,但找不到任何相关的解决方案来满足我的要求。
请帮助我,覆盖的方法名称是什么?...
在派生的 ItemsSource 的静态构造函数中调用 OverrideMetadata
class:
public class MyItemsControl : ItemsControl
{
static MyItemsControl()
{
ItemsSourceProperty.OverrideMetadata(
typeof(MyItemsControl),
new FrameworkPropertyMetadata(OnItemsSourcePropertyChanged));
}
private static void OnItemsSourcePropertyChanged(
DependencyObject obj, DependencyPropertyChangedEventArgs e)
{
((MyItemsControl)obj).OnItemsSourcePropertyChanged(e);
}
private void OnItemsSourcePropertyChanged(DependencyPropertyChangedEventArgs e)
{
var oldCollectionChanged = e.OldValue as INotifyCollectionChanged;
var newCollectionChanged = e.NewValue as INotifyCollectionChanged;
if (oldCollectionChanged != null)
{
oldCollectionChanged.CollectionChanged -= OnItemsSourceCollectionChanged;
}
if (newCollectionChanged != null)
{
newCollectionChanged.CollectionChanged += OnItemsSourceCollectionChanged;
// in addition to adding a CollectionChanged handler
// any already existing collection elements should be processed here
}
}
private void OnItemsSourceCollectionChanged(
object sender, NotifyCollectionChangedEventArgs e)
{
// handle collection changes here
}
}
如何覆盖 PropertyChangedCallback
预定义的依赖关系 属性 ItemsSource
在 WPF ItemsControl
.
我开发了一个继承自ItemsControl
的WPF自定义控件。因为我使用了预定义的依赖关系 属性 ItemsSource
。因为我需要在 Collection
更新后监控和检查数据。
我在google中搜索了很多,但找不到任何相关的解决方案来满足我的要求。
请帮助我,覆盖的方法名称是什么?...
在派生的 ItemsSource 的静态构造函数中调用 OverrideMetadata
class:
public class MyItemsControl : ItemsControl
{
static MyItemsControl()
{
ItemsSourceProperty.OverrideMetadata(
typeof(MyItemsControl),
new FrameworkPropertyMetadata(OnItemsSourcePropertyChanged));
}
private static void OnItemsSourcePropertyChanged(
DependencyObject obj, DependencyPropertyChangedEventArgs e)
{
((MyItemsControl)obj).OnItemsSourcePropertyChanged(e);
}
private void OnItemsSourcePropertyChanged(DependencyPropertyChangedEventArgs e)
{
var oldCollectionChanged = e.OldValue as INotifyCollectionChanged;
var newCollectionChanged = e.NewValue as INotifyCollectionChanged;
if (oldCollectionChanged != null)
{
oldCollectionChanged.CollectionChanged -= OnItemsSourceCollectionChanged;
}
if (newCollectionChanged != null)
{
newCollectionChanged.CollectionChanged += OnItemsSourceCollectionChanged;
// in addition to adding a CollectionChanged handler
// any already existing collection elements should be processed here
}
}
private void OnItemsSourceCollectionChanged(
object sender, NotifyCollectionChangedEventArgs e)
{
// handle collection changes here
}
}