<wpftk:DataGrid Grid.Row="1"
        x:Name="myOrdersGrid"
        ColumnHeaderStyle="{DynamicResource FilterColumnHeaderStyle}"
        CanUserResizeColumns="True"
        VerticalAlignment="Stretch"
        HorizontalAlignment="Stretch">

  <wpftk:DataGrid.Resources>
    <Style x:Key="FilterColumnHeaderStyle" TargetType="{x:Type Primitives:DataGridColumnHeader}">
      <Setter Property="Template">
        <Setter.Value>
          <ControlTemplate TargetType="{x:Type Primitives:DataGridColumnHeader}">
            <WrapPanel Width="50" Orientation="Vertical">
              <ContentPresenter Content="{TemplateBinding Content}" HorizontalAlignment="Stretch"  />
              <TextBox Text="Hello" FontSize="10" Background="OldLace" HorizontalAlignment="Center" />
            </WrapPanel >
          </ControlTemplate>
        </Setter.Value>
      </Setter>
    </Style>
  </wpftk:DataGrid.Resources>

  <wpftk:DataGrid.Columns>
    <wpftk:DataGridTextColumn SortMemberPath="Name" Binding="{Binding Name}" IsReadOnly="True"/>
    <wpftk:DataGridTextColumn SortMemberPath="Name" Binding="{Binding Price}" IsReadOnly="True"/>
  </wpftk:DataGrid.Columns>
</wpftk:DataGrid>

<Style x:Key="FilterColumnHeaderStyle" TargetType="{x:Type Primitives:DataGridColumnHeader}">
      <Setter Property="ContentTemplate">
        <Setter.Value>
          <DataTemplate>
            <WrapPanel Orientation="Vertical">
              <ContentPresenter Content="{TemplateBinding Content}" HorizontalAlignment="Stretch"  />
              <TextBox Text="{grid:GridFilter UpdateSourceTrigger=PropertyChanged}"
                  Visibility="{Binding ElementName=FilterCheckbox, Path=IsChecked, Converter={StaticResource b2v}}"
                  FontSize="10" Width="50" Background="OldLace" HorizontalAlignment="Center" />
            </WrapPanel >
          </DataTemplate>
        </Setter.Value>
      </Setter>
    </Style>