How to search data stored in file and display it in list box when search button click?

I want to search the data, which is stored in a file, when I click on the search button, and show it in list box, in Window phone 7 app..

UI design like this

<ComboBox x:Name="comboPriority" Height="43" VerticalAlignment="Center" SelectedIndex="1" HorizontalAlignment="Center" Width="246" OpacityMask="#BFBAD5AF" Foreground="Black" Margin="12,61,198,503">
    <ComboBoxItem Content="Art" x:Name="minimum" Foreground="Black" Background="White" FontSize="28"></ComboBoxItem>
    <ComboBoxItem Content="Science" x:Name="maximum" Foreground="Black" Background="White"  FontSize="28" ></ComboBoxItem>
    <ComboBoxItem Content="Entertenment" Foreground="Black" Background="White"  FontSize="28"></ComboBoxItem>
    <ComboBoxItem Content="Politics" Foreground="Black" Background="White"  FontSize="开发者_高级运维28"></ComboBoxItem>
</ComboBox>

<Button Name="btnSearch" Content="Search" Height="70" Width="150" Margin="293,47,13,483" Click="btnSearch_Click" BorderBrush="#FF100505" Foreground="#FF070101" />
<ListBox Height="359" HorizontalAlignment="Left" Margin="10,168,0,0" Name="lbList" VerticalAlignment="Top" Width="433" />

When I select the category related data from file can display in list box..

You should read up on Data Binding