Code

private void OnRuler_SizeChanged(object sender, SizeChangedEventArgs e)
        {
            if (m_Diagram.Bounds.Width < e.NewSize.Width)
            {
                Rect newBounds = new Rect(m_Diagram.Bounds.X, m_Diagram.Bounds.Y,
                    e.NewSize.Width, m_Diagram.Bounds.Height);
                m_Diagram.Bounds = newBounds;
            }
        }
 

Code

<UserControl x:Class="Technologist.TPDEDiagram"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:mf="clr-namespace:MindFusion.Diagramming.Wpf;assembly=MindFusion.Diagramming.Wpf"
    xmlns:cmds="clr-namespace:Technologist.InterfaceCommands"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:navigation="http://schemas.actiprosoftware.com/winfx/xaml/navigation"
    xmlns:shared="http://schemas.actiprosoftware.com/winfx/xaml/shared"
    HorizontalAlignment="Stretch" VerticalAlignment="Stretch"
    HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="*"/>
            <RowDefinition Height="0"/>
        </Grid.RowDefinitions>
        <mf:Ruler Name="m_Ruler" Margin="0,0,0,2" VerticalScaleVisible="Collapsed"
            HorizontalScaleVisible="Collapsed" SizeChanged="OnRuler_SizeChanged">
            <mf:Ruler.Document>
                <mf:Diagram Name="m_Diagram"
                        ShowDisabledHandles="false"
                        ModificationStart="AutoHandles"
                        SnapToAnchor="OnCreateOrModify"
                        LinkHitDistance="3"
                        ShowGrid="False"
                        AlignToGrid="True"
                        AllowSelfLoops="False"
                        AllowDrop="True"
                        AllowSplitLinks="True"
                        AllowUnanchoredLinks ="False"
                        AllowUnconnectedLinks="False"
                        AutoScroll="True"
                        GridStyle="Points"
                        LinkShape="Cascading"
                        AllowLinkCursor="Arrow"
                        AutoResize="RightAndDown"
                        InplaceEditAcceptOnEnter="False"
                        InplaceEditCancelOnEsc="True"
                        AllowInplaceEdit="False"
                        DragDrop.DragOver="OnDiagram_DragOver"
                        DragDrop.Drop="OnDiagram_Drop"
                        LinkCreated="OnDiagram_LinkCreated"
                        LinkCreating="OnDiagram_LinkCreating"
                        LinkModifying="OnDiagram_LinkModifying"
                        LinkModified="OnDiagram_LinkModified"
                        LinkActivated="OnDiagram_LinkActivated"
                        LinkDeactivated="OnDiagram_LinkDeactivated"
                        SelectionChanged="OnDiagram_SelectionChanged"
                        ContextMenuOpening="OnDiagram_ContextMenuOpening"
                        KeyDown="OnDiagram_KeyDown"
                        EnterInplaceEditMode="OnDiagram_EnterInplaceEditMode"
                        LeaveInplaceEditMode="OnDiagram_LeaveInplaceEditMode"
                        NodeModified="OnDiagram_NodeModified"
                        NodeDeleted="OnDiagram_NodeDeleted"
                        NodeCreated="OnDiagram_NodeCreated"
                        NodeDeleting="OnDiagram_NodeDeleting"
                        NodeActivated="OnDiagram_NodeActivated"
                        NodeDeactivated="OnDiagram_NodeDeactivated"
                        NodeDoubleClicked="OnDiagram_NodeDoubleClicked"
                        NodeModifying="OnDiagram_NodeModifying"
                        ZoomFactorChanged="OnDiagram_ZoomFactorChanged"
                        DirtyChanged="OnDiagram_DirtyChanged">
                </mf:Diagram>
            </mf:Ruler.Document>
        </mf:Ruler>
        <StackPanel Grid.Row="1" Visibility="Collapsed" Orientation="Vertical">
            <Label Content="{Resx ResxName=Technologist.TPDEDiagram,
                                    Key=BreadcrumbInitTitle}" Visibility="Collapsed"/>
        </StackPanel>
    </Grid>
</UserControl>

 

Code

	  private void OnDiagram_ZoomFactorChanged(object sender, EventArgs e)
	  {
		Rect newBounds = new Rect();
		if (m_Diagram.ZoomFactor >= 100)
		    newBounds = new Rect(m_Diagram.Bounds.X, m_Diagram.Bounds.Y,
			  m_Ruler.ActualWidth / (100 / m_Diagram.ZoomFactor),
			  m_Ruler.ActualHeight / (100 / m_Diagram.ZoomFactor));
		else
		    newBounds = new Rect(m_Diagram.Bounds.X, m_Diagram.Bounds.Y,
			  m_Ruler.ActualWidth * (100 / m_Diagram.ZoomFactor),
			  m_Ruler.ActualHeight * (100 / m_Diagram.ZoomFactor));
		m_Diagram.Bounds = newBounds;
	  }