I lost an hour of development due to the error
The “ValidateXAML” task failed unexpectedly
This error is extremely unfriendly in that it does not reference which XAML page caused the failure. It turns out in one of my page modifications I had set data binding on a checkbox to my underlying data object like this.
<CheckBox Checked = “{Binding MyBooleanPorpertyOnMyDataClass}” />
I should have done it this way.
<CheckBox IsChecked = “{Binding MyBooleanPorpertyOnMyDataClass}” />
Talk about an easy error to overlook. The “Checked” attribute of the checkbox is not a property, but rather an event. You cannot data bind to an event. The solution was to find and fix my type-o. This blog post gave me a hint as to what might be the problem.
http://eightyeightpercentnerd.blogspot.com/2009/01/silverlight-2-c-data-binding-and-event.html
Many thanks to yamroll, the poster. Hopefully this error will be improved in Silverlight 3 and point the developer to the cause of the error. This has the potential to be a very easy mistake for many developers and waste much more than an hour’s time trying to discover the root cause.