Data binding is a way for your app's UI to display data, and optionally to stay in sync with that data.Data binding allows you to separate the concern of data from the concern of UI, and that results in a simpler conceptual model as well as better readability, testability, and maintainability of your app.Here's a very rudimentary implementation of a class that we could use as a binding source.

One way of doing that is to derive the class that represents your binding source from Dependency Object, and expose a data value through a Dependency Property.

That's how a Framework Element becomes observable.

If you're using then you don't need that attribute. That implementation of Host View Model, and its property Next Button Text, are only appropriate for one-time binding.

But one-way and two-way bindings are extremely common, and in those kinds of binding the UI automatically updates in response to changes in the data values of the binding source.

Framework Elements are good binding sources right out of the box. This really just involves implementing a single event named Property Changed. Note For C /CX, you implement Windows:: UI:: Xaml:: Data:: INotify Property Changed, and the binding source class must either have the Bindable Attribute or implement ICustom Property Provider. When you author a one-way or a two-way binding to that property (we'll show how later), the resulting binding object subscribes to the Property Changed event.

A more lightweight way of making a class observable—and a necessary one for classes that already have a base class—is to implement System. When that event is raised, the binding object's handler receives an argument containing the name of the property that has changed.

Basically what is happening is the after update event doesn't fire until i actually click on the list box. When the user double clicks on the value it a db.execute statement which is an Update SQL statement to put it in the right state, either yes or no. What I'm having a problem with though is that based on what values are chosen Private Sub lst Patron Types Include_After Update() For x = 0 To lst Patron Types Include. It doesn't become active until I have moved it over and then click on the listbox of selected variable.

Basically what is happening is the after update event doesn't fire until i actually click on the list box.

You can use data binding to simply display values from a data source when the UI is first shown, but not to respond to changes in those values.