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PO"All" value for a Combobox Data Filter in WPF
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  1. PO"All" value for a Combobox Data Filter in WPF
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    copied!<p>During the construction of user control I populate the combobox with some data. Works fine. I have Status.ID as valuePath and Status.Name as displayPath.</p> <pre><code>cmb.ItemsSource = dbEntities.Status </code></pre> <p>The comobox will be used as a filter control and I need to insert some value for "All", which will be used as the empty filter.</p> <p>First I tried a funny solution:</p> <pre><code>ObjectSet objectSet= dbEntities.Status; Status stAll = new Status(); stAll.ID = -1; stAll.Name = "All"; objectSet.AddObject(stAll); cmb.ItemsSource = objectSet; </code></pre> <p>For some reason the object is not added to the objectSet. It didnt throw any exception either.</p> <p>Then I tried to insert it manually to the first index but I got the error: "Operation is not valid while ItemsSource is in use. Access and modify elements with ItemsControl.ItemsSource instead." My code looked like:</p> <pre><code>cmb.ItemsSource = entities.Status; cmb.Items.Insert(0,"All"); </code></pre> <p>Both didnt work. What would be the easiest way to add that line to the combobox? The error message got me confused. I am not sure how to use the ItemsSource for such a purpose. </p> <p>edit: I did not have enough rep to answer my own question so here is the working code. Thanks Craig again.</p> <pre><code>CompositeCollection comp = new CompositeCollection(); comp.Add(new CollectionContainer {Collection = dbEntities.Status}); Status stAll = new Status(); stAll.ID = -1; stAll.Name = "All"; comp.add(stAll); cmb.ItemsSource = comp; //do whatever filter you want when the selected value is -1 </code></pre>
 

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