UpdateSourceTrigger UpdateSourceTrigger UpdateSourceTrigger UpdateSourceTrigger Enum


Defines constants that indicate when a binding source is updated by its binding target in two-way binding.

public : enum class UpdateSourceTrigger
enum class winrt::Windows::UI::Xaml::Data::UpdateSourceTrigger : int32_t
public enum UpdateSourceTrigger
Public Enum UpdateSourceTrigger
Windows 10 requirements
Device family
Windows 10 (introduced v10.0.10240.0)
API contract
Windows.Foundation.UniversalApiContract (introduced v1)


Default Default Default Default 0

Use default behavior from the dependency property that uses the binding. In Windows Runtime, this evaluates the same as a value with PropertyChanged.

Explicit Explicit Explicit Explicit 2

The binding source is updated only when you call the BindingExpression.UpdateSource method.

LostFocus LostFocus LostFocus LostFocus 3

The binding source is updated whenever the binding target element loses focus.

PropertyChanged PropertyChanged PropertyChanged PropertyChanged 1

The binding source is updated whenever the binding target value changes. This is detected automatically by the binding system.



The default UpdateSourceTrigger value is Default rather than PropertyChanged for legacy reasons. Previous XAML frameworks enabled a way to register a dependency property with a value that influenced what its default binding update behavior does. That dependency property behavior isn't implemented in the Windows Runtime.