如何手动更新多重绑定
我在绑定方面遇到了问题。 Rectangle.Fill 依赖属性已通过转换器绑定到 ObservableCollection。尽管 ObservableCollection 实现了 INotifyCollectionChanged，但绑定并未更新。不过，我设法通过将我的委托附加到集合的更改通知事件并手动刷新绑定来解决此问题：
void ColorsCollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
{
BindingExpression b = colorRectangle.GetBindingExpression(Rectangle.FillProperty);
if (b != null)
b.UpdateTarget();
}
但是，最近我将 Binding 更改为 MultiBinding，并且上述解决方案停止工作（b 为 null）。有没有办法强制多重绑定更新目标属性？
最好的问候——斯普克。
I had a problem with the Binding. The Rectangle.Fill dependency property was bound to an ObservableCollection with the converter. Although the ObservableCollection implements INotifyCollectionChanged, the binding was not updated. I managed, however, to solve this by attaching my delegation to the collection's change notification event and refreshing the binding manually:
void ColorsCollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
{
BindingExpression b = colorRectangle.GetBindingExpression(Rectangle.FillProperty);
if (b != null)
b.UpdateTarget();
}
Lately, however, I changed the Binding to MultiBinding, and the above solution stopped working (the b is null). Is there a way to force the Multibinding to update the target property?
Best regards -- Spook.
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对于多重绑定，绑定表达式是
MultiBindingExpression，它继承自BindingExpressionBase，但不是继承自BindingExpression。因此，GetBindingExpression对于多重绑定返回 null。相反，您可以使用BindingOperations.GetMultiBindingExpression：For a multibinding, the binding expression is a
MultiBindingExpression, which inherits fromBindingExpressionBase, but not fromBindingExpression. SoGetBindingExpressionreturns null for a multibinding. Instead you can useBindingOperations.GetMultiBindingExpression: