UpdateSourceTrigger Enum


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

public enum class UpdateSourceTrigger
/// [Windows.Foundation.Metadata.ContractVersion(Windows.Foundation.UniversalApiContract, 65536)]
enum class UpdateSourceTrigger
[Windows.Foundation.Metadata.ContractVersion(typeof(Windows.Foundation.UniversalApiContract), 65536)]
public enum UpdateSourceTrigger
Public Enum UpdateSourceTrigger

Windows requirements

Device family
Windows 10 (introduced in 10.0.10240.0)
API contract
Windows.Foundation.UniversalApiContract (introduced in v1.0)


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 2

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

LostFocus 3

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

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.

Version history

Windows version SDK version Value added
1709 16299 LostFocus

Applies to