しばらく経ちましたが、同じ問題に遭遇したので、解決策を共有したいと思います。それが誰かに役立つことを願っています。
public class UpdateSourceBehavior : Behavior<System.Windows.Interactivity.TriggerBase>
{
internal const string TargetElementPropertyLabel = "TargetElement";
static UpdateSourceBehavior()
{
TargetElementProperty = DependencyProperty.Register
(
TargetElementPropertyLabel,
typeof(FrameworkElement),
typeof(UpdateSourceBehavior),
new PropertyMetadata(null)
);
}
public static readonly DependencyProperty TargetElementProperty;
[Bindable(true)]
public FrameworkElement TargetElement
{
get { return (FrameworkElement)base.GetValue(TargetElementProperty); }
set { base.SetValue(TargetElementProperty, value); }
}
public PropertyPath TargetProperty { get; set; }
protected override void OnAttached()
{
base.OnAttached();
this.InitializeMembers();
base.AssociatedObject.PreviewInvoke += this.AssociatedObject_PreviewInvoke;
}
protected override void OnDetaching()
{
base.AssociatedObject.PreviewInvoke -= this.AssociatedObject_PreviewInvoke;
base.OnDetaching();
}
private void AssociatedObject_PreviewInvoke(object sender, PreviewInvokeEventArgs e)
{
this.m_bindingExpression.UpdateSource();
}
private void InitializeMembers()
{
if (this.TargetElement != null)
{
var targetType = this.TargetElement.GetType();
var fieldInfo = targetType.GetFields(BindingFlags.Public | BindingFlags.Static | BindingFlags.FlattenHierarchy)
.FirstOrDefault(fi => fi.Name == this.TargetProperty.Path + "Property");
if (fieldInfo != null)
this.m_bindingExpression = this.TargetElement.GetBindingExpression((DependencyProperty)fieldInfo.GetValue(null));
else
throw new ArgumentException(string.Format("{0} doesn't contain a DependencyProperty named {1}.", targetType, this.TargetProperty.Path));
}
else
throw new InvalidOperationException("TargetElement must be assigned to in order to resolve the TargetProperty.");
}
private BindingExpression m_bindingExpression;
}