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POUnable to access object from another thread
 

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    <p>I understand that this has been discussed on other questions but I am pulling my hair out here- clearly missing something obvious. I'll try to give you some background info so here goes...</p> <p>I have a UI thread which was freezing up so I created a background worker to do all the heavy processing to keep my UI interactive.</p> <p>I need to generate coordinates for some arcs/ paths which I then draw on a canvas. The background worker processes and runs it's work completed method where it stores the PathGeometry along with some other data in a list. I then called an update() method in my UI thread, from my backgroundworker, using the object I passed into the backgroundworker.</p> <p>My problem is that when I begin to build the Path objects in the UI thread (it wouldn't let me build them in the backgroundworker thread) I am unable to access the PathGeometries. My object is a CommunicationArc and it holds the PathGeometry, opacity, colour etc.</p> <pre><code>The calling thread cannot access this object because a different thread owns it. </code></pre> <p>I can access other parts of the object but <strong>not</strong> the PathGeometry and I do not know why. The backgroundworker surely has finished as the workcomplete method has run and the Arcs are all stored in my list. I simply want to read the arcs in my UI thread, process them a little bit more and go on to draw them.</p> <p>I have tried using the Dispatcher from my UI thread like so:</p> <pre><code>arc.pathGeometry.Dispatcher.BeginInvoke((Action)(() =&gt; { MessageBox.Show(arc.pathGeometry.ToString()); })); </code></pre> <p>But I'm not really sure if what I am doing is right and various methods to call the Dispatcher either don't do anything or lock everything on the BeginInvoke().</p> <p>Any help would be great, I feel like I'm going in circles here!</p>
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    1. COTry calling [Freeze](http://msdn.microsoft.com/en-us/library/ms557735.aspx) on your PathGeometry objects in the background thread before using them in the UI thread.
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