如何将已绑定到多绑定的控件转换为多绑定

Question

假设我有一个FrameworkElement，它已经绑定到XAML中的转换器。在编程上，我希望在运行时将绑定附加到现有绑定中-例如在控件的加载事件中，有效地使其成为多绑定。

如何获取现有的绑定(例如，Visibility属性)

Answer 1

你可以这样做:

var oldBinding = BindingOperations.GetBinding(element, UIElement.VisibilityProperty);
var newBinding = new MultiBinding { Converter = ... };
var firstBinding = new Binding
{
    Path = oldBinding.Path,
    Source = oldBinding.Source // or RelativeSource or ElementName
};
var secondBinding = new Binding
{
    ...
};
newBinding.Bindings.Add(firstBinding);
newBinding.Bindings.Add(secondBinding);
BindingOperations.SetBinding(element, UIElement.VisibilityProperty, newBinding);