请问下listview里面有一列用了combobox控件，添加信息之后如何把添加进combobox的值显示出来？

  <ListView Margin="369,0,23,148" Name="Isvproductatt" Height="109" VerticalAlignment="Bottom" FontWeight="Bold">
                <ListView.View>
                    <GridView x:Name="gvProductAttr">
                        <GridViewColumn CellTemplate="{StaticResource FirstCell}" Width="30"></GridViewColumn>
                        <GridViewColumn Header="ATTRIBUTE ID" Width="1" DisplayMemberBinding="{Binding Path=AttributeId}"></GridViewColumn>
                        <GridViewColumn Header="ATTRIBUTE NAME" Width="180" DisplayMemberBinding="{Binding Path=AttributeName}"></GridViewColumn>
                        <GridViewColumn Header="ATTRIBUTE VALUE" Width="180" >
                            <GridViewColumn.CellTemplate>
                                <DataTemplate>
                                    <ComboBox Name="cmbAttibutes"  Width="120" Text="{Binding Path=AttributeValue, Mode=TwoWay}"  MouseLeftButtonDown="cmbAttibutes_MouseLeftButtonDown"  DropDownOpened="cmbAttibutes_DropDownOpened"  SourceUpdated="cmbAttibutes_SourceUpdated" IsEditable="True">
                                    </ComboBox>
                                </DataTemplate>
                            </GridViewColumn.CellTemplate>
                        </GridViewColumn>
                    </GridView>
                </ListView.View>
            </ListView>  
这个是那个listview，<ComboBox Name="cmbAttibutes"  Width="120" Text="{Binding Path=AttributeValue, Mode=TwoWay}"  MouseLeftButtonDown="cmbAttibutes_MouseLeftButtonDown"  DropDownOpened="cmbAttibutes_DropDownOpened"  SourceUpdated="cmbAttibutes_SourceUpdated" IsEditable="True">  </ComboBox>  是listview里面用的那个combobox，我添加信息后想显示出来，现在combobox里面的不能显示