Question : Summarizing a network

Hello all,
Could some one let me know the answer to the below question and shortly let me know how its done or give my some links with more info. But, please try to answer it first. Thanks,  

. How should the following Networks be summarized?
172.16.12.0/24
172.16.13.0/24
172.16.14.0/24
172.16.15.0/24

Answer : Summarizing a network

Example of using CellTemplate/CellEditTemplate in DataGrid (w/ComboBox).

<UserControl x:Class="Silverlight.Page"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:data="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data"
    xmlns:src="clr-namespace:Silverlight"
    Width="400" Height="300">
    <UserControl.Resources>
        <src:CityProvider x:Key="cityProvider"/>
    </UserControl.Resources>
    <Grid x:Name="LayoutRoot" Background="White">
        <data:DataGrid x:Name="dataGrid" AutoGenerateColumns="False">
            <data:DataGrid.Columns>
                <data:DataGridTextColumn Header="Street Name" Binding="{Binding StreetName}"/>
                <data:DataGridTemplateColumn Header="City">
                    <data:DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <TextBlock Text="{Binding CityInfo.CityName}" />
                        </DataTemplate>
                    </data:DataGridTemplateColumn.CellTemplate>
                    <data:DataGridTemplateColumn.CellEditingTemplate>
                        <DataTemplate>
                            <ComboBox SelectedItem="{Binding CityInfo, Mode=TwoWay}"
                                      ItemsSource="{Binding CityList, Source={StaticResource cityProvider}}"
                                      DisplayMemberPath="CityName"
                                  />
                        </DataTemplate>
                    </data:DataGridTemplateColumn.CellEditingTemplate>
                </data:DataGridTemplateColumn>
                <data:DataGridTextColumn Header="Zip Code" Binding="{Binding ZipCode}"/>
            </data:DataGrid.Columns>
        </data:DataGrid>
    </Grid>
</UserControl>

Above was from http://weblogs.asp.net/manishdalal/archive/2008/09/28/combobox-in-datagrid.aspx

HTH
Ashok