Adrian Vinca's blog

Hi Victor,

IMHO, triggers allow a declarative way (in the xaml) of implementing some conditional behaviors. This brings some advantages: toolability (e.g. see how Expression Interactive Designer displays the triggers) and improves the reusability (if you want to reuse your styled control into another project, you just need to copy the xaml). There are also different types of triggers:

EventTrigger - A class that controls a set of actions to activate in response to an event

DataTrigger - A single Style data conditional dependency driver (this one is very useful when combined with databinding)

Trigger - represents a condition for a property value that, when met, causes the associated Setter to change a property value.

Thanks,
- Adrian

First of all, triggers don't replace the events. You can still use events and code behind for your controls (and for more complicated operations, using triggers could be difficult or even impossible).

"Copy the xaml" wasn't perhaps the best way to express the fact that reusability could be a little bit easier. Just like in an HTML you can create a style for a button, in Windows Presentation Foundation you can create a style and reuse it across your controls. The Windows Presentation Foundation offers ways to reuse the source without copying the code (you can use resource dictionaries) or you can use assemblies.

A similar question was posted on the Windows Presentation Foundation forums (you may want to check there for other opinions): http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=264517&SiteID=1

You could also check the tutorial "Creating a simple style with one trigger" to see how Expression Interactive Designer allows creating triggers and how you can switch between different states and visualize the behavior (e.g. you click on the IsMouseOver state and see how your control looks like when the mouse is over).

Thanks,
- Adrian