When/how to check for brokenrules?

jas_nhs posted on Thursday, September 28, 2006

I have a grid (Telerik) with an edit template, all of which is bound to a csla data source. A common requirement is to check user input when in edit mode (a grid row expands to an edit form with update/cancel options). The idea of course would be to ntercept the update event and display an error message and force correction of the error. I want to use the broken-rules collection to do this, and have set up custom rules etc.

To enable checking of broken rules (br), I create a 'trial' object and look at the br collection and if all is ok, proceed with the update. The br have to be checked here as this is the only place where I have access to the editing controls, and I need to keep the edit form in view etc. If I leave it to 'commit time' (update event on csla data source) the edit form is closed and it is inappropriate to display an error msg then.

Problem is, I can create a new trial object with 'wrong' values yet the br count is still zero and IsValid is true - I 'm obviously not understanding just when the rules are checked (if I save and then re-open for editing, the rule violations are detected). I can't call ValidationRules.CheckRules() at this level, and the object does not have a CheckRules method... Is there a way to invoke the rule-checking explicitly on an in-memory object? What event causes the rules to be checked?

The object in question is an editable child.

Thanks

James.

jas_nhs replied on Thursday, September 28, 2006

Thanks - Yes, simple as that, except that DatePortal_Create is part of generated code and I would need to check the implications of adding this call. Also, I did not make totally clear that the problem also arises when updating existing data.

I have worked round this by hand-editing the generated code with a call to CheckRules when you set the contentious properties. I wondered if PropertyHasChanged might have called CheckRules but it doesn't seem to, leaving the general issue of how to force a rule check when you want to e.g. you have an object and are modifying a property with some value from an external source.

Perhaps the best (?) thing is to call CheckRules each time you set a property...?

jas

ajj3085 replied on Thursday, September 28, 2006

Jas,

Rules should be getting checked as each property changes values, but this only happens if you remember to call PropertyHasChanged( "MyProperty" ). Of course if you forget that in your property setters, databinding won't work properly either.

HTH
Andy

Fabio replied on Thursday, September 28, 2006

For me, absolutly not.
CheckRules() without parameter check all rules and i need to do that, sometimes, only after creation.
Obviuslly you can do that when you want but you must pay that with performance.

CheckRules("PropertyName") is called by PropertyHasChanged("PropertyName") in the set of a property only when the property changed..... bah?!? depend on how you had implemented the set of the property...

Bye.
Fabio.