Zoom diagram with in the grid

I place the diagram in the Grid. When the Grid is resized, how to scale/zoom/resize the diagram in side the grid as well. Please provide sample code.

<Grid HorizontalAlignment="Stretch" VerticalAlignment="Stretch" x:Name="gridDiagram" Margin="100,50,100,50" MinWidth="350" MinHeight="250" dx:ThemeManager.ThemeName="Office2013" >

<Border BorderThickness="1" BorderBrush="Black" CornerRadius="10" Margin="0">

<go:Diagram x:Name="myDiagram" IsReadOnly="True" InitialScale="NaN"

Padding="10" AllowScroll="True"

VerticalContentAlignment="Center"

HorizontalContentAlignment="Center"

GridSnapEnabled="True"

GridVisible="True" >

<go:Diagram.PanningTool>

<go:PanningTool WheelBehavior="Zooms" />

</go:Diagram.PanningTool>

<go:Diagram.Layout>

<go:TreeLayout />

</go:Diagram.Layout>

<go:Node Id="PrintGrid">

<Grid go:Part.LayerName="Background" go:Part.Selectable="False"

go:Part.LayoutId="None" go:Node.Avoidable="False"

go:Part.InDiagramBounds="False" go:Part.Printable="False"

go:Node.LocationElementName="GridPattern"

go:Part.Visible="False">

<Grid.RowDefinitions>

<RowDefinition Height="Auto" />

<RowDefinition Height="Auto" />

</Grid.RowDefinitions>

<Grid.ColumnDefinitions>

<ColumnDefinition Width="Auto" />

<ColumnDefinition Width="Auto" />

</Grid.ColumnDefinitions>

<Border BorderBrush="Black" BorderThickness="1" Background="White">

<go:GridPattern Grid.Row="0" Grid.Column="0" x:Name="GridPattern">

<Path Stroke="Purple" StrokeThickness="2" go:GridPattern.Figure="HorizontalLine" />

<Path Stroke="Purple" StrokeThickness="2" go:GridPattern.Figure="VerticalLine" />

</go:GridPattern>

</Border>

<Polygon Grid.Row="0" Grid.Column="1" Fill="Gray"

Points="0 0 20 20 0 20" VerticalAlignment="Top" />

<Rectangle Grid.Row="0" Grid.Column="1" Fill="Gray"

Width="20" Margin="0 20 0 0" />

<Polygon Grid.Row="1" Grid.Column="0" Fill="Gray"

Points="0 0 20 0 20 20" HorizontalAlignment="Left" />

<Rectangle Grid.Row="1" Grid.Column="0" Fill="Gray"

Height="20" Margin="20 0 0 0" />

<Rectangle Grid.Row="1" Grid.Column="1" Fill="Gray"

Width="20" Height="20" />

</Grid>

</go:Node>

</go:Diagram>

</Border>

</Grid