How does “UpdateSourceTrigger” affect bindings?


UpdateSourceTrigger” decides when the data should get updated between WPF objects that are binded. In other word should data get updated in lost focus event, in data change event etc.
There are four modes by which “UpdateSourceTrigger” can be defined:-

  • Default: – If it’s a text property then data is updated during lost focus and for normal
    properties data updates in property change event.
  • PropertyChanged: – In this setting data is updated as soon as the value is changed.
  • LostFocus: – In this setting data is updated as soon as lost focus event occurs.
  • Explicit: – In this setting the data is updated manually. In other words to update data
    between two WPF object you need to call the below code.
BindingExpression binding =txt1.GetBindingExpression(TextBox.TextProperty);
binding.UpdateSource();