O'Reilly logo

Microsoft® Windows® Workflow Foundation Step by Step by Kenn Scribner

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Creating a Custom ActivityValidator

By now, I’m sure you’ve seen the small red circle containing an exclamation mark that appears in activities that have unfinished configurations in the visual workflow designer. A Code activity that has nothing established for its ExecuteCode property will display this indicator, for example. What causes this?

The answer is that an activity validator forces this behavior. A validator examines the properties of its associated activity and inserts errors into an error collection if any properties are missing or invalid. The validator is asked to reevaluate the rules it applies to the activity properties when the state of the designer changes (that is, when new activities are added or properties change) and when ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required