Business Rules contex getting lost ?

olawal posted on Wednesday, November 23, 2011

the following code is in  my buisnesslistbase class which is a collection of my AssignMent object.  Basically when the collection that of Assignment objects changes i.e

Protected Overrides Sub OnCollectionChanged(e As System.Collections.Specialized.NotifyCollectionChangedEventArgs)
		MyBase.OnCollectionChanged(e)
 
		If Me.AssignmentCollectionChanged IsNot Nothing Then
			Me.AssignmentCollectionChanged.Invoke()
		End If
	End Sub

 I invoke the callback function that checks the rules in the dataportal fetch. of the holder

Me.Assignments.AssignmentCollectionChanged = Sub() Me.BusinessRules.CheckRules()

 now this happens intermitently , if the rule is broken the following line is executed :

I have a buisnes s rule that when the rule fails the following function is executed

If returnMessage.Length > 2 Then
				returnMessage = returnMessage.Substring(0, returnMessage.Length - 1)
				context.AddErrorResult(returnMessage)
End If

Now for some reason the method that does is building the collection does not for 
always retain the error result when the the following check is run:

For Each assignment In assignmentCollection.Assignments
			If assignment.BrokenRulesCollection.Count > 0 Then
				canSave = False
				For Each assignErr In assignment.BrokenRulesCollection
					errorMessages.Add(assignErr.Description)
				Next
			End If
Next
 
Somtimes it works and the broken rules collection does contain the errors raised 
any ideas ?
 

JonnyBee replied on Thursday, November 24, 2011

Hi,

1: You should never call BusinessRules.CheckRules() on a background thread.  The CheckRules method may raise OnPropertyChanged and you will get cross thread exception when databound to UI (rich client).

2: You should not run async rules on the serverside of the data portal. If deployed in a 3 tier layer your object will be serialized and returned to the client in the middle of rule checking (and possible in an indetermined/invalid state).

3: If deployed in a 3 tier layer or using the AutoCloneOnUpdate (which is on by default)  you must reestablish the AssignmentCollectionChanged event in the OnDeserialized event.

4: You could also look at the BusinessRules.GetAllbrokenRules() method that will safely traverse your object structure and return the broken rules.

5: Is your (parent object) rules depending on values from Assignments)? If they are then I'd rather call <bo>.CheckObjectRules() or PropertyHasChanged(propertyInfo) for that specific property. When running in a rich client these 2 methods are the ONLY ones that will notify the UI of changes in property/rules.

 

olawal replied on Monday, November 28, 2011

I'm not using a rich client thankfully, it is just a jquery html grid application , I did not write the original code, so I am trying to navigate it and figure out what  they were doing prior to my arrival. 

I have a feeling you are right that the issue is due to where the checkRules is being called from, I am really at a loss here trying to figure out what the contractor was thinking lol. 

I am thinking of just prevalidating from the UI instead of having to re-write thier CSLA code. 

First I will try the BusinessRules.GetAllbrokenRules()  to see if the broken rulues are captured there I guess

I don't think I can use your option 5 becase I do not have a rich client like silverlight.

let me know what you think and thanks