OK, so the title is a little ambitious, but there is nothing wrong with setting yourself lofty aims!
Silverlight textblock binding not updating
In the following example, the As a result, the Text Block shows the same text (because the source changes) as the user enters text into the Text Box, as illustrated by the following screenshot of the sample: If you have a dialog or a user-editable form and you want to defer source updates until the user is finished editing the fields and clicks "OK", you can set the Update Source Trigger value of your bindings to Explicit, as in the following example: You can use the same technique for properties of other controls, but keep in mind that most other properties have a default Update Source Trigger value of Property Changed.
For more information, see the Update Source Trigger property page.
This topic describes how to use the Update Source Trigger property to control the timing of binding source updates. This means if an application has a Text Box with a data-bound Text Box.
Text property has a default Update Source Trigger value of Lost Focus.
With WPF this is done easily by setting the Update Source Trigger property to Property Changed in the Binding definition, unfortunately this is not available for Silverlight.
A workaround that I found for this was to add a Key Up event to the required Text Box and update the binding in code behind.
When the Window loads, the textbox's do not bind to the properties in my model.
I verify within the debugger that the data context is set to the model object and the model's properties are properly assigned.
You can refer to the samples cited in this topic for more information.