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    <p>WPF classes have thread affinity. What this means is that all changes to those objects must be in the same thread where they were created. It truly is difficult to create a user interface API that is thread-safe, so Microsoft chose to keep it singlethreaded and force run-time checking to make sure of it.</p> <p>That said, there are a few options you have to perform your sort in a background thread, and then apply it in the UI thread. The first option is to copy your SortableCollection into a plain old List or Array and perform the sort in the background. Once the background thread is complete, you use a Dispatcher to execute code in the UI thread. Every UI element in WPF extends <code>System.Windows.Threading.DispatcherObject</code> and most extend <code>System.Windows.Freezable</code>. The DispatcherObject is where you get the Dispatcher to execute code in the UI thread.</p> <p>Logically, the execution would be something like this:</p> <pre><code>public void BackgroundSort() { List&lt;T&gt; items = new List&lt;T&gt;(this.ToArray()); BackgroundSortDelegate del = Sort; del.BeginInvoke(SortCompleted, del); } private void SortCompleted(IAsyncResult result) { BackgroundSortDelegate del = result.AsyncState as BackgroundSortDelegate; List&lt;T&gt; items = del.EndInvoke(result); this.Dispatcher.Invoke(()=&gt;{this.Collection = items;}); } </code></pre> <p>The short explanation of what happened is that the background worker/delegate is using a copy of the items in this list. Once the sort is complete, we are calling the Dispatcher object and invoking an action. In that action we are assigning the new sorted list back to our object.</p> <p>The key to assigning the result of any background work within the UI thread is to use the UI's Dispatcher object. There's actually probably a half dozen ways to invoke a background worker in C#, but the approach to get your work in a background thread into the UI thread is the same.</p>
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    1. USBerin Loritsch
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    1. POHow to create an observableCollection Sortable and multithreading
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    1. COThanks Berin for explanation, But where I have to put this methods? In the SortableCollection or in the event Handler of declanching the sort method?
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    2. COWherever it makes the most sense to you logically. The benefit of doing it in the SortableCollection is that you can pass just the SortableCollection to different methods and they can interact with it automatically. Just a note of warning: Dispatcher is an expensive operation. It's fine called occasionally, but in a tight loop it will really slow things down.
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A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

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