Filter xml data present as a object using linq to xml

hello friends,
I want to filter xmldata present as a item source of dynamically generated stack panel consisting of textblock,combobox and textbox.What i want is since textblock displays the selected element(which i have already figured out) user should select a filter criteria from the combobox and add text to the textbox and based on 3 filters,,it should filter and should display the filtered content.On searching the internet i found that linq to xml was a feasilble way.

here is the xaml
codexaml

<ListView Height="222" HorizontalAlignment="Left" Margin="341,24,0,0" Name="listView1" VerticalAlignment="Top" Width="290" removed="Green" 
                  AllowDrop="True" 
                  DragDrop.Drop="listview_drop" 
                  DragDrop.DragEnter="treeview_dragenter" ItemsSource="{Binding XPath=self::*}">
            <ListView.ItemTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Horizontal" HorizontalAlignment="Stretch" x:Name="stc">
                        <TextBlock Text="{Binding Path=Name}" Margin="0,0,3,0" x:Name="abc"/>
                        <ComboBox Margin="0,0,3,0" x:Name="cbox1">
                            <ComboBoxItem Content="Less Than"/>
                            <ComboBoxItem Content="Greater Than"/>
                            <ComboBoxItem Content="Equals"/>
                        </ComboBox>
                        <TextBox Margin="0,0,3,0" Width="50" x:Name="textbox1" />
                        <Button x:Name="but1" Height="25" Width="35" Click="click" Content="gen" />
                    </StackPanel>
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>

And the c# code behind

private void click(object sender, RoutedEventArgs e)
{
    var button = sender as Button;
    var parent = button.Parent as FrameworkElement;
    var textBox = parent.FindName("textbox1") as TextBox;
    var textbl = parent.FindName("abc") as TextBlock;
    var com=parent.FindName("cbox1")as ComboBox;

    Xelement filter= (Xelement)((XmlDataProvider)Resources["xmlDataProvider"]).Data;

}

My problem is that on working with xelement,Iam getting a invalid type exception that it cannot convert system.xml.xmldocument to system.xml.linq .

Tags: C# (C# 4.0), XML, WPF, LINQ