Hi, I have a question? How I can change the state of the check box control positioned in the header? I need to check or uncheck this control after some operation as delete all rows etc...

(IG 2012.1 - silverlight)

Thanks

<ig:XamGrid Grid.Row="1" HorizontalAlignment="Left" Name="gridElencoDocumenti" Height="280" VerticalAlignment="Top" AutoGenerateColumns="False" ColumnWidth="*"
CellDoubleClicked="gridElencoDocumenti_CellDoubleClicked"
RowSelectorClicked="gridElencoDocumenti_RowSelectorClicked"
CellClicked="gridElencoDocumenti_CellClicked">
<ig:XamGrid.Columns>
<ig:CheckBoxColumn Key="IsChecked" HeaderText=" " Width="52">
<ig:CheckBoxColumn.HeaderTemplate>
<DataTemplate>
<CheckBox Checked="CheckBox_Checked" Unchecked="CheckBox_Unchecked"/>
</DataTemplate>
</ig:CheckBoxColumn.HeaderTemplate>
</ig:CheckBoxColumn>
<ig:TextColumn Key="IdDocumento" HeaderText=" " Width="50" IsReadOnly="True" Visibility="Collapsed"/>
<ig:TextColumn Key="NomeDocumento" HeaderText="Documento" Width="*" IsReadOnly="True"/>
<ig:ImageColumn Key="ClasseControlImage" ImageHeight="15" ImageWidth="15" HeaderText="Stato" Width="62" />
</ig:XamGrid.Columns>
</ig:XamGrid>