I would like to do a small suggestion to improve validations performance.
Problem description
The IsDirty can’t be used in validation rules because its value is not updated until the validation rules are checked. So if the first property that is edited on a business object is involved in a validation rule then that validation can’t check the IsDirty property because of it will get a wrong value (IsDirty = False).
Validations that need executing commands against the database are very expensive. When an object is clean we can avoid checks against the database assuming that all properties are valid in the database (the database constraints get it). Performance can be improved so much.
Solution
If method BusinessBase.PropertyHasChanged calls MarksDirty before calling CheckRules then the property IsDirty will have the right value when validations are performed.
Do the following change to BusinessBase:
<Serializable()> _
Public MustInherit Class BusinessBase
Inherits UndoableBase
...
#Region " IsNew, IsDeleted, IsDirty "
...
Protected Overridable Sub PropertyHasChanged(ByVal propertyName As String)
MarkDirty(True)
ValidationRules.CheckRules(propertyName)
OnPropertyChanged(propertyName)
End Sub
...
#End Region
...
End Class
RockfordLhotka:
Not a bad idea, but I'm interested to hear if anyone can think of scenarios where this would break their code?
I have a lot of BOs and rules and none of them check IsDirty as part of their Validation rules. So this small change would not break my code.
Just to verify, this change really only affects the first Property thatis modified on a BO because after that the BO is dirty. I can't see where this would hurt anything.
Joe
When a business object is edited, after the first property is changed, the object is dirty by definition. If we find that IsDirty property is useful on any validation rule then the IsDirty property should have the right value at the time of performing the validation. I see it as a consistency issue.
Setting the IsDirty property to True before calling CheckRules only may affect validations doe to the business object does not raise any notification (event) when MarkDirty is called from PropertyHasChanged.
I can’t imagine a situation where it may be problematic this small change, and I am also curious about how could be a use case which would be conflictive with.
Thanks every body for your attention.
Benjamin
OK, I’ve slipped this changed into 3.5.
Rocky
I am just looking to get a better understanding of CSLA with this question. How can we get into a validation routine without the object being dirty?
You can call ValidationRules.CheckRules() pretty much any time
you want – even before the object has been “changed”. For
example, if you don’t trust the data from the database (or web service,
or wherever you are getting your data) then you might call this method at the
end of your DataPortal_Fetch(). The object isn’t dirty at that point, but
it might be invalid.
Rocky
From: stanc
[mailto:cslanet@lhotka.net]
Sent: Monday, March 03, 2008 7:51 AM
To: rocky@lhotka.net
Subject: Re: [CSLA .NET] RE: MarkDirty called before CheckRules
I am just looking to get a better understanding of CSLA with this question.
How can we get into a validation routine without the object being dirty?
Copyright (c) Marimer LLC