Problem with WPF PTracker sample?

I have heard of this issue with WPF tab control.  I think if you google “WPF Tab Control Template Load”, you will probably find a solution to tab control problem.  We are not using tab control in our software, we are faking it with stand-along buttons and grid to load selected controls into.  Not sure if this will address your load problem though.  You might need to have check your Provider.Data == null prior to firing refresh in Loaded.

Sergey Barskiy

Principal Consultant

office: 678.405.0687 | mobile: 404.388.1899

Microsoft Worldwide Partner of the Year | Custom Development Solutions, Technical Innovation

Hi,

I've been building user controls based on the Wpf PTracker sample, which uses the Loaded event to referesh the CslaDataProvider.

The problem is that Load and Unload will fire ANY time the control is loaded or unloaded from the visual tree... this manifests itself in different ways.  One reason Unload / Load will refire is if the user changes their OS theme.  Another reason seems to be if you drop the user control into the DocumentContent portion of the XamDockManager from Infragistics.  As you change tabs, the Unload event fires for any user control which is no longer being displayed, and fires again when the user control is displayed.

This created a weird issue for me; I created a new part edit user control and added it to a tab.  I edited the part data and saved, and created another new one without closing the original tab.  When I was done, I clicked back to the first tab... and the screen cleared and said I was working on a new part. 

Has anyone else hit this problem yet?  I'm also looking for a reliable way to do cleanup; my user control starts a DispatchTimer, and I'd like to shut it off when the control is "closed."

Andy

I do not necessarily see sample as wrong or right, but more like a training tool/sample code.  I think, there is a steep learning curve involved in moving to WPF from WinForms, and it is just a matter of doing it and seeing what works.  I do not follow PTracker exactly in my application, but I did use it on occasion when I started with WPF.  General principal still works  - single frame with multiple controls loaded into a placeholder in main frame in response to user actions.  All controls in my case user data providers to get and update the data, and this is probably the only constant for screen to screen.  Like I mentioned, I do not use tab controls, but this is not a major deal.

Sergey Barskiy

Principal Consultant

office: 678.405.0687 | mobile: 404.388.1899

Microsoft Worldwide Partner of the Year | Custom Development Solutions, Technical Innovation

Ya, it looks like this is pretty normal, but it caught me off guard.  I think this may have been asked before, but is it wrong to use the UI samples as "best practice?"  I'm still fairly new to Wpf, so when building my Csla Wpf application, I'm tending to mimic what the PTracker does.