Thursday, May 2, 2013

UI Annotation using Business Rules

XAF already provides strong and flexible validation for any object that fits specified Rules with build-in the Validation Module. In this post you can find a sample XAF application which extends the Validation to provide support for Warning/Information messages.

The implementation uses any Validation Business Rule that exists in XAF’s Application Model. Below we see the default ones but its applicable to custom business rules as well.


The sample code extends the Application Model of IModelRuleBase and by using one more property like RuleType marks the rule as warning or information as shown:


When the Validation occurs this implementation will not raise exceptions for Warning and Information Rules and will change their notification icon accordingly.





By default, it is also possible to create business rules that evaluated when an object is changed  by using the ObjectSpaceObjectChanged custom context (see also Contextual Validation Concepts).

To use this RuleType functionality discussed today in your XAF Applications you need to download the sample from The functionality is described by just one controller in RuleTypeController.cs which is spanned across the platform agnostic and platform depended projects.

Note: I “borrow” the code for RuleType support from our community project expandframework and for one more time we clearly see how flexible is XAF and how powerful to provide reusable solutions!

P.S.: The original eXpand implementation has code support using a RuleTypeAttribute as well as ListView support and can be found in Xpand.ExpressApp.Validation, Xpand.ExpressApp.Validation.Win and Xpand.ExpressApp.Validation.Web assemblies (See also this discussion in eXpand’s forums).

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