Share via

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.

Explicit 2

The binding source is updated only when you call the BindingExpression.UpdateSource method. (Not supported for x:Bind.)

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. This evaluates as a PropertyChanged update behavior for most dependency properties, but evaluates as LostFocus for the TextBox.Text property.

Version history

Windows version SDK version Value added
1709 16299 LostFocus

Applies to