Liew,

>Do you mean after adding the function CallCheckRules() in ABusinessObject, I can just call Me.BO.CallCheckRules() directly? Besides, I noticed that all the values for validation are required to assign to the current row before the validation. Am I missing some steops before calling the CheckRules method? Thanks.

With MM .NET automatic two-way data binding, the business object raises a PreSaving event that tells all user interface controls to bind their data back to the business object. This happens automatically when you call SaveDataSet() on the business object. You can also raise it programmatically by calling the business object's CallStateChange() method. For example:

Me.oBizObj.CallStateChange(mmBusinessState.PreSaving)

Best Regards,