<DataGrid.ColumnHeaderStyle>
                    <Style TargetType="{x:Type DataGridColumnHeader}">
                        <Setter Property="Background" Value="#4F83B5" />
                        <Setter Property="Foreground" Value="#ffffff" />
                        <Setter Property="ContentTemplate">
                            <Setter.Value>
                                <DataTemplate>
                                    <StackPanel Orientation="Vertical">
                                        <TextBlock   Margin="10"/>
                                    </StackPanel>
                                </DataTemplate>
                            </Setter.Value>
                        </Setter>
                    </Style>
                </DataGrid.ColumnHeaderStyle>

<DataGridTextColumn Width="*"
                                        Binding="{Binding Path=var_val}"
                                        Header="{x:Static Resources:Strings.str}" />

<DataGridTextColumn.Header>
                            <TextBlock>...</TextBlock>
</DataGridTextColumn.Header>