DoRefresh behavior if DataPortalException thrown

DoRefresh behavior if DataPortalException thrown

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lukky posted on Saturday, May 01, 2010

Hi all,

Playing with CSLA 4 preview. Just a small WPF test application.

Right now the behavior of DoRefresh is to catch any DataPortal exception and set the Error property on the ViewModel.

In many (if not all) scenarios, I want to "blank out" all bound controls in such situation, so I'd set Model = null. I wonder if that shouldn't be DoRefresh's default behavior ? I'd like to hear the pros and cons of the actual vs. proposed behavior.

My POV is that if a call to DoRefresh fails, I certainly don't want to leave the controls displaying the old object's data. For example, if I call DoRefresh("GetCustomer", ID); and the ID is not a valid one, then of course no object will be returned from the DataPortal.

Thanks for sharing your ideas.


lukky replied on Monday, May 03, 2010


I was seeing it going near the bottom ;-)

RockfordLhotka replied on Monday, May 03, 2010

OnError() is a virtual method, so you can override OnError() and set Model to null.

This is one of those things where I could make the behavior work either way to make some subset of users happy. But if I set Model to null, it is harder for someone to block that behavior than if I leave Model alone - because it is easy to override OnError() and make it null.

lukky replied on Monday, May 03, 2010

Thanks Rocky,

I think you're right on this. That's why I wanted to "test the water".

Overriding OnError sounds like a good way to handle this situation.

Maybe my question has a broader scope than what I suspect ? I mean, how a "no data" situation should be handled is certainly different from app to app. In my case, as I said, I blank out the controls (through databinding). Others might have different techniques ?


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