How to make WPF DataGrid scrollbar cover the non-scrollable area as well?

I'm not sure if this is just my m开发者_开发问答achine (WinXP SP3), because I have not seen it in other people's screenshots.

It looks to me that the scrollbars in DataGrid only cover the scrollable area. That means, the column and row header areas and the bottom right corner are shown in background color, which looks ugly to me. How can I make the scrollbar to extend to the edge of the control (like more regular control)? Is there is property in DataGrid for this?

You may not see it if you didn't change the background color of the DataGrid. I have a screenshot here to illustrate this problem.

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Okay, after some struggling, I figured it out myself. In case anybody cares...put this style into you App.xaml.

<ControlTemplate x:Key="SelectAllButtonTemplate" TargetType="{x:Type Button}">
    <Grid>
        <Rectangle x:Name="Border"
             Fill="{DynamicResource {x:Static SystemColors.ControlBrushKey}}" 
             SnapsToDevicePixels="True" />
        <Polygon x:Name="Arrow"
           HorizontalAlignment="Right"
           VerticalAlignment="Bottom"
           Margin="8,8,3,3"
           Opacity="0.15"
           Fill="Black"
           Stretch="Uniform"
           Points="0,10 10,10 10,0" />
    </Grid>
    <ControlTemplate.Triggers>
        <Trigger Property="IsMouseOver" Value="True">
            <Setter TargetName="Border" Property="Stroke" Value="{DynamicResource {x:Static SystemColors.ControlDarkBrushKey}}" />
        </Trigger>
        <Trigger Property="IsPressed" Value="True">
            <Setter TargetName="Border" Property="Fill" Value="{DynamicResource {x:Static SystemColors.ControlDarkBrushKey}}" />
        </Trigger>
        <Trigger Property="IsEnabled" Value="False">
            <Setter TargetName="Arrow" Property="Visibility" Value="Collapsed" />
        </Trigger>
    </ControlTemplate.Triggers>
</ControlTemplate>

<Style TargetType="{x:Type DataGrid}">
    <Setter Property="Background"
            Value="{DynamicResource {x:Static SystemColors.ControlBrushKey}}"/>
    <Setter Property="Foreground"
            Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
    <Setter Property="BorderBrush" Value="#FF688CAF" />
    <Setter Property="BorderThickness" Value="1" />
    <Setter Property="RowDetailsVisibilityMode" Value="VisibleWhenSelected" />
    <Setter Property="ScrollViewer.CanContentScroll"
            Value="true"/>
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type DataGrid}">
                <Border Background="{TemplateBinding Background}"
              BorderBrush="{TemplateBinding BorderBrush}"
              BorderThickness="{TemplateBinding BorderThickness}"
              SnapsToDevicePixels="True"
              Padding="{TemplateBinding Padding}">
                    <ScrollViewer   Focusable="false"
                        Name="DG_ScrollViewer">
                        <ScrollViewer.Template>
                            <ControlTemplate TargetType="{x:Type ScrollViewer}">
                                <Grid>
                                    <Grid.RowDefinitions>
                                        <RowDefinition Height="Auto"/>
                                        <RowDefinition Height="*"/>
                                        <RowDefinition Height="Auto"/>
                                    </Grid.RowDefinitions>

                                    <Grid.ColumnDefinitions>
                                        <ColumnDefinition Width="Auto"/>
                                        <ColumnDefinition Width="*"/>
                                        <ColumnDefinition Width="Auto"/>
                                    </Grid.ColumnDefinitions>

                                    <!--Left Column Header Corner -->
                                    <Button Command="{x:Static DataGrid.SelectAllCommand}"
                        Width="{Binding RelativeSource={RelativeSource AncestorType={x:Type DataGrid}}, Path=CellsPanelHorizontalOffset}"
                        Template="{StaticResource SelectAllButtonTemplate}"
                        Focusable="false"
                        Visibility="{Binding RelativeSource={RelativeSource AncestorType={x:Type DataGrid}}, Path=HeadersVisibility, Converter={x:Static DataGrid.HeadersVisibilityConverter}, ConverterParameter={x:Static DataGridHeadersVisibility.All}}" />
                                    <!--Column Headers-->
                                    <DataGridColumnHeadersPresenter Grid.Column="1" 
                                                   x:Name="PART_ColumnHeadersPresenter"
                                                   Visibility="{Binding RelativeSource={RelativeSource AncestorType={x:Type DataGrid}}, Path=HeadersVisibility, Converter={x:Static DataGrid.HeadersVisibilityConverter}, ConverterParameter={x:Static DataGridHeadersVisibility.Column}}"/>

                                    <!--DataGrid content-->
                                    <ScrollContentPresenter x:Name="PART_ScrollContentPresenter" Grid.Row="1" Grid.ColumnSpan="2" CanContentScroll="{TemplateBinding CanContentScroll}" />

                                    <!-- Changed Grid.Row="1" to Grid.Row="0" Grid.RowSpan="2" to make the scrollbar start from top -->
                                    <ScrollBar Grid.Row="0" Grid.RowSpan="2" Grid.Column="2" Name="PART_VerticalScrollBar"
                                         Orientation="Vertical"
                                         Maximum="{TemplateBinding ScrollableHeight}"
                                         ViewportSize="{TemplateBinding ViewportHeight}"
                                         Value="{Binding Path=VerticalOffset, RelativeSource={RelativeSource TemplatedParent}, Mode=OneWay}"
                                         Visibility="{TemplateBinding ComputedVerticalScrollBarVisibility}"/>

                                    <!--Grid Grid.Row="2" Grid.Column="1">
                  <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="{Binding RelativeSource={RelativeSource AncestorType={x:Type dg:DataGrid}}, Path=NonFrozenColumnsViewportHorizontalOffset}"/>
                    <ColumnDefinition Width="*"/>
                  </Grid.ColumnDefinitions>
                  <ScrollBar Grid.Column="1"
                             Name="PART_HorizontalScrollBar"
                             Orientation="Horizontal"
                             Maximum="{TemplateBinding ScrollableWidth}"
                             ViewportSize="{TemplateBinding ViewportWidth}"
                             Value="{Binding Path=HorizontalOffset, RelativeSource={RelativeSource TemplatedParent}, Mode=OneWay}"
                             Visibility="{TemplateBinding ComputedHorizontalScrollBarVisibility}"/>

                </Grid-->
                                    <!-- Make the scrollbar to start from left edge -->
                                    <ScrollBar Grid.Column="0" Grid.Row="2" Grid.ColumnSpan="2"
                                            Name="PART_HorizontalScrollBar"
                                            Orientation="Horizontal"
                                            Maximum="{TemplateBinding ScrollableWidth}"
                                            ViewportSize="{TemplateBinding ViewportWidth}"
                                            Value="{Binding Path=HorizontalOffset, RelativeSource={RelativeSource TemplatedParent}, Mode=OneWay}"
                                            Visibility="{TemplateBinding ComputedHorizontalScrollBarVisibility}"/>
                                </Grid>
                            </ControlTemplate>
                        </ScrollViewer.Template>
                        <ItemsPresenter SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
                    </ScrollViewer>
                </Border>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
    <Style.Triggers>
        <Trigger Property="IsGrouping" Value="true">
            <Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
        </Trigger>
    </Style.Triggers>
</Style>