</DataGrid.Columns>
        <DataGrid.GroupStyle>
            <!--Default GroupStyle-->
            <GroupStyle>
                <GroupStyle.Panel>
                    <ItemsPanelTemplate>
                        <DataGridRowsPresenter/>
                    </ItemsPanelTemplate>
                </GroupStyle.Panel>
                <GroupStyle.HeaderTemplate>
                    <DataTemplate>
                        <StackPanel>
                            <TextBlock Text="{Binding Path=Name}" FontWeight="Bold" Padding="3"/>
                        </StackPanel>
                    </DataTemplate>
                </GroupStyle.HeaderTemplate>
                <GroupStyle.ContainerStyle>
                    <Style TargetType="{x:Type GroupItem}">
                        <Setter Property="Template">
                            <Setter.Value>
                                <ControlTemplate TargetType="{x:Type GroupItem}">
                                    <Expander x:Name="exp"
                                  BorderBrush="#FFA4B97F"
                                  BorderThickness="0,0,0,1"
                                  IsExpanded="{Binding Path=Items[0].IsExpanded}">
                                        <Expander.Header>
                                            <DockPanel TextBlock.FontWeight="Bold">
                                                <TextBlock Text="{Binding Name}" Margin="5,0,5,0" Foreground="Blue" />
                                                <!--<TextBlock Text="{Binding Path=ItemCount}"/>-->
                                                <TextBlock Text="  (" />
                                                <TextBlock Text="{Binding Path=ItemCount}"/>
                                                <TextBlock Text=" Items )" />

                                            </DockPanel>
                                        </Expander.Header>
                                        <ItemsPresenter/>
                                    </Expander>
                                </ControlTemplate>
                            </Setter.Value>
                        </Setter>
                    </Style>
                </GroupStyle.ContainerStyle>
            </GroupStyle>
        </DataGrid.GroupStyle>
    </DataGrid>![enter image description here][1]