Unchecking One of the child checkboxes should uncheck the parent checkbox in WPF MVVM pattern

First two ways are working for me, the third and fourth points mentioned below by me are not working

1)if i check the header check box ,all the child checkbox will be checked

2)if uncheck, all will be unchecked

3)if everything is checked..if i uncheck one child checkbox...header checkbox will be unchecked

4)if i check one by one all the child checkbox....header checkbox will be checked.

Here is my code

<DataGridTemplateColumn>
<DataGridTemplateColumn.Header>
<CheckBox Content="Included" x:Name="headerCheckBox" />
</DataGridTemplateColumn.Header>
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<CheckBox Name="chkselectAll" IsChecked="{Binding IsChecked,ElementName=headerCheckBox,Mode=OneWay}"></CheckBox>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn> 

could I get some help here. How do I achieve it in xaml?