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POTwo-way binding combobox to enum
 

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    <p>I have a View that is linked to my ViewModel using a DataTemplate, like this</p> <pre><code>&lt;DataTemplate DataType="{x:Type ViewModels:ViewModel}"&gt; &lt;Views:View /&gt; &lt;/DataTemplate&gt; </code></pre> <p>The ViewModel holds a property <code>ProcessOption</code> that is of type <code>MyEnum?</code>, where <code>MyEnum</code> is a custom enumeration that has let's say 3 values: <code>Single</code>, <code>Multiple</code> and <code>All</code>. I am trying to bind a combobox to this property, so the approach I am following is:</p> <p>ViewModel has a property of <code>List&lt;string&gt;</code> that is </p> <pre><code>public List&lt;string&gt; Options { get { return Enum.GetNames(typeof(MyEnum)).ToList(); } } </code></pre> <p>to which I bind the <code>ItemsSource</code> property of the <code>Combobox</code>. Then, in addition to the <code>ProcessOption</code> property, the ViewModel also has an <code>OptionName</code> property (of <code>string</code>), which is intended to hold the selected option's name. The ViewModel implements <code>INotifyPropertyChanged</code> and both properties raise the <code>PropertyChanged</code> event in their setters. The binding I am using then is:</p> <pre><code>&lt;ComboBox ItemsSource="{Binding Options}" SelectedItem="{Binding OptionName}" SelectedValue="{Binding ProcessOption}"/&gt; </code></pre> <p>This works fine up to this point. Initially the combobox is empty and both properties are <code>null</code>, and when the user selects an option this is propagated to the ViewModel as it should.</p> <p>The problem appears when I load the data from a Database, and I want to load the controls with initial values. In this case, in the ViewModel's constructor I have this:</p> <pre><code>this.ProcessOption = objectFromDB.ProcessOption // this is the value restored from DB, let's say it is MyEnum.Multiple this.OptionName = Options.First(x =&gt; x.Equals(Enum.GetName(typeof(MyEnum), objectFromDB.ProcessOption))); </code></pre> <p>The problem is, although the above sets the two properties to their correct values, they are later set to null from the <code>Combobox</code> binding, so the initial values are not kept. I have also tried to do something like <code>if (value == null) { return; }</code> in the properties' setters, in which case they have the correct values after the View loads, however the <code>Combobox</code> still does not display the correct option, it is empty.</p> <p>I should also note that I've also tried setting <code>IsSynchronisedWithCurrentItem</code> and it doesn't make any difference, apart from the fact that the first element is displayed instead of the combobox being empty.</p> <p>Can anyone help with this binding? Any help will be very much appreciated, this is driving me crazy!</p>
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    1. USBrian Day
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    1. COHave you tried to bind only on the SelectedItem or SelectedValue property of the combobox instead of both? I think your problem could be in that direction.
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    2. COWow, that did it. Can't believe I didn't try this, binding only to SelectedItem works, and then I can get the other property from the one that's bound. Thanks!!
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