I am unable to set selected value of "comboBox" in "ListView".

Here is XAML code.

**Propertyname:** LISTTOPICS

```
<ListView x:Name="gridTopics" 
          ItemsSource="{Binding Path=TOPICSINFO}" Width="310">
    <ListView.View>
        <GridView>
            <GridView.Columns>
                <GridViewColumn Header="Associated Topics" >
                    <GridViewColumn.CellTemplate>
                        <DataTemplate>
                            <ComboBox ItemsSource="{Binding LISTTOPICS}" 
                                      SelectedValue="{Binding SelectedTopic.SELECTEDTOPIC}" />
                        </DataTemplate>
                    </GridViewColumn.CellTemplate>
                </GridViewColumn>
            </GridView.Columns>
        </GridView>
    </ListView.View>
</ListView>

```

And C# code is

```
public class SelectedTopic : ObservableObject
{
    private static string selectedTopic;
    public static string SELECTEDTOPIC
    {
        get { return selectedTopic; }
        set { selectedTopic = value; }
    }
}

```