WPF Diagram Designer - Part 3

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                    xmlns:s="clr-namespace:DiagramDesigner"
                    xmlns:c="clr-namespace:DiagramDesigner.Controls">

  <!-- Connector Style -->
  <Style TargetType="{x:Type s:Connector}">
    <Setter Property="Width" Value="8"/>
    <Setter Property="Height" Value="8"/>
    <Setter Property="Cursor" Value="Cross"/>
    <Setter Property="SnapsToDevicePixels" Value="true"/>
    <Setter Property="Template">
      <Setter.Value>
        <ControlTemplate TargetType="{x:Type s:Connector}">
          <Grid>
            <!-- transparent extra space makes connector easier to hit -->
            <Rectangle Fill="Transparent" Margin="-2"/>
            <Rectangle Fill="Lavender" StrokeThickness="1" Stroke="#AA000080"/>
          </Grid>
        </ControlTemplate>
      </Setter.Value>
    </Setter>
  </Style>

  <!-- ConnectorDecoratorTemplate Default Template -->
  <ControlTemplate x:Key="ConnectorDecoratorTemplate" TargetType="{x:Type Control}">
    <Grid Margin="-5">
      <s:Connector Orientation="Left" VerticalAlignment="Center" HorizontalAlignment="Left"/>
      <s:Connector Orientation="Top" VerticalAlignment="Top" HorizontalAlignment="Center"/>
      <s:Connector Orientation="Right" VerticalAlignment="Center" HorizontalAlignment="Right"/>
      <s:Connector Orientation="Bottom" VerticalAlignment="Bottom" HorizontalAlignment="Center"/>
    </Grid>
  </ControlTemplate>

  <!-- ResizeDecorator Default Template -->
  <ControlTemplate x:Key="ResizeDecoratorTemplate" TargetType="{x:Type Control}">
    <Grid Opacity="0.7" SnapsToDevicePixels="true">
      <c:ResizeThumb Height="3" Cursor="SizeNS" Margin="0 -4 0 0"
                     VerticalAlignment="Top" HorizontalAlignment="Stretch"/>
      <c:ResizeThumb Width="3" Cursor="SizeWE" Margin="-4 0 0 0"
                     VerticalAlignment="Stretch" HorizontalAlignment="Left"/>
      <c:ResizeThumb Width="3" Cursor="SizeWE" Margin="0 0 -4 0"
                     VerticalAlignment="Stretch" HorizontalAlignment="Right"/>
      <c:ResizeThumb Height="3" Cursor="SizeNS" Margin="0 0 0 -4"
                     VerticalAlignment="Bottom" HorizontalAlignment="Stretch"/>
      <c:ResizeThumb Width="7" Height="7" Cursor="SizeNWSE" Margin="-6 -6 0 0"
                     VerticalAlignment="Top" HorizontalAlignment="Left"/>
      <c:ResizeThumb Width="7" Height="7" Cursor="SizeNESW" Margin="0 -6 -6 0"
                     VerticalAlignment="Top" HorizontalAlignment="Right"/>
      <c:ResizeThumb Width="7" Height="7" Cursor="SizeNESW" Margin="-6 0 0 -6"
                     VerticalAlignment="Bottom" HorizontalAlignment="Left"/>
      <c:ResizeThumb Width="7" Height="7" Cursor="SizeNWSE" Margin="0 0 -6 -6"
                     VerticalAlignment="Bottom" HorizontalAlignment="Right"/>
    </Grid>
  </ControlTemplate>

  <!-- DragThumb Default Template -->
  <Style TargetType="{x:Type c:DragThumb}">
    <Setter Property="Template">
      <Setter.Value>
        <ControlTemplate TargetType="{x:Type c:DragThumb}">
          <Rectangle Fill="Transparent"/>
        </ControlTemplate>
      </Setter.Value>
    </Setter>
  </Style>

  <!-- DesignerItem Style -->
  <Style TargetType="{x:Type s:DesignerItem}">
    <Setter Property="MinWidth" Value="25"/>
    <Setter Property="MinHeight" Value="25"/>
    <Setter Property="SnapsToDevicePixels" Value="True"/>
    <Setter Property="Template">
      <Setter.Value>
        <ControlTemplate TargetType="{x:Type s:DesignerItem}">
          <Grid DataContext="{Binding RelativeSource={RelativeSource TemplatedParent}}">
            <!-- PART_DragThumb -->
            <c:DragThumb x:Name="PART_DragThumb" Cursor="SizeAll"/>
            <!-- PART_ResizeDecorator -->
            <Control x:Name="PART_ResizeDecorator"
                     Visibility="Collapsed"
                     Template="{StaticResource ResizeDecoratorTemplate}"/>
            <!-- PART_ContentPresenter -->
            <ContentPresenter x:Name="PART_ContentPresenter"
                              HorizontalAlignment="Stretch"
                              VerticalAlignment="Stretch"
                              Content="{TemplateBinding ContentControl.Content}"
                              Margin="{TemplateBinding ContentControl.Padding}"/>
            <!-- PART_ConnectorDecorator -->
            <Control x:Name="PART_ConnectorDecorator"
                     Visibility="Hidden"
                     Template="{StaticResource ConnectorDecoratorTemplate}"/>
          </Grid>
          <ControlTemplate.Triggers>
            <DataTrigger Value="True" Binding="{Binding RelativeSource={RelativeSource Self},Path=IsSelected}">
              <Setter TargetName="PART_ResizeDecorator" Property="Visibility" Value="Visible"/>
            </DataTrigger>
            <Trigger Property="IsMouseOver" Value="true">
              <Setter TargetName="PART_ConnectorDecorator" Property="Visibility" Value="Visible"/>
            </Trigger>
            <DataTrigger Value="True" Binding="{Binding RelativeSource={RelativeSource Self},Path=IsDragConnectionOver}">
              <Setter TargetName="PART_ConnectorDecorator" Property="Visibility" Value="Visible"/>
            </DataTrigger>
          </ControlTemplate.Triggers>
        </ControlTemplate>
      </Setter.Value>
    </Setter>
  </Style>

</ResourceDictionary>