OK, sorry for the overly broad question, but let's see what you guys suggest....

I have a WPF ListView loaded by an XML file, using XAML (code below) 

I have a second XML file with items that match what is in my ListView. However, if there is *not* a match in the 2nd file, then I want that ListItem disabled.

A simple example:

My ListView has in it: 

```
                   Joe
                   Fred
                   Jim  

```

(because it was loaded with the first XML file)

My second XML file has (essentially): 

```
                  Joe
                  Jim

```

I want the ListView to somehow consume this second file as well, resulting in "Fred" being disabled.

I am assuming that it would be some sort of "Filter" I would apply somewhere in XAML.

```
<ListView Name="lvwSourceFiles" 
          Margin="11,93,0,12" VerticalContentAlignment="Center" 
          HorizontalAlignment="Left" Width="306"
          Cursor="Hand" TabIndex="6" 
          ItemsSource="{Binding}"
          SelectionMode="Multiple"
          SelectionChanged="lvwSourceFiles_SelectionChanged" >
    <ListBox.DataContext>
        <XmlDataProvider x:Name="xmlSourceFiles" XPath="AssemblyUpdaterSource/sources/source/File" />
    </ListBox.DataContext>
    <ListView.ItemContainerStyle>
        <Style TargetType="{x:Type ListViewItem}">
            <EventSetter Event="PreviewMouseRightButtonDown"
                         Handler="OnSourceListViewItemPreviewMouseRightButtonDown" />
        </Style>
    </ListView.ItemContainerStyle>
</ListView>

```