Dynamic Send Activity in WF4

<sap:ActivityDesigner x:Class="RKiss.Activities.DynamicSend.Design.SendQueueMessageDesigner"    
                      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"       
                      xmlns:s="clr-namespace:System;assembly=mscorlib"        
                      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"      
                      xmlns:sap="clr-namespace:System.Activities.Presentation;assembly=System.Activities.Presentation"      
                      xmlns:sapv="clr-namespace:System.Activities.Presentation.View;assembly=System.Activities.Presentation"       
                      xmlns:conv="clr-namespace:System.Activities.Presentation.Converters;assembly=System.Activities.Presentation"        
                      mc:Ignorable="d"        
                      xmlns:d="http://schemas.microsoft.com/expression/blend/2008"      
                      xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" >
    <sap:ActivityDesigner.Resources>
        <conv:ArgumentToExpressionConverter x:Key="expressionConverter"/>
    
    <DataTemplate x:Key="Collapsed">
        <StackPanel>
            <TextBlock>This is the collapsed view</TextBlock>
        </StackPanel>
    </DataTemplate>
    <DataTemplate x:Key="Expanded">
        <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
             <RowDefinition Height="*"/>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto"/>           
            <ColumnDefinition Width="*"/>                                                                                                                                                                   
        </Grid.ColumnDefinitions>                                                                                                                   
            <TextBlock Grid.Row="0" Grid.Column="0" Margin="2">Queue Name:</TextBlock>
            <sapv:ExpressionTextBox Expression="{Binding Path=ModelItem.QueueName, Converter={StaticResource expressionConverter}}"                                                                                                                                                                                                                                                                                                                                                                                                                   
                            ExpressionType="s:String"
                            OwnerActivity="{Binding ModelItem}"
                            Grid.Row="0" Grid.Column="1" HorizontalAlignment="Left" Width="177" Margin="2"/>
             <TextBlock Grid.Row="1" Grid.Column="0" Margin="2">DLQ Name:</TextBlock>
             <sapv:ExpressionTextBox Expression="{Binding Path=ModelItem.DeadQueueName, Converter={StaticResource expressionConverter}}"                                     
                            ExpressionType="s:String"
                            OwnerActivity="{Binding ModelItem}"
                            Grid.Row="1" Grid.Column="1" HorizontalAlignment="Left" Width="177" Margin="2"/>
             <TextBlock Grid.Row="2" Grid.Column="0" Margin="2">Machine Mame:</TextBlock>
             <sapv:ExpressionTextBox Expression="{Binding Path=ModelItem.MachineName, Converter={StaticResource expressionConverter}}"                                     
                            ExpressionType="s:String"
                            OwnerActivity="{Binding ModelItem}"
                            Grid.Row="2" Grid.Column="1" HorizontalAlignment="Left" Width="177" Margin="2"/>
             <sap:WorkflowItemPresenter Item="{Binding ModelItem.Body}"
                               HintText="Drop Send Activity"
                               Margin="6"
                               Grid.Row="4"
                               Grid.Column="0"
                               Grid.ColumnSpan="2"/>
    </Grid>
   </DataTemplate>

    <Style x:Key="ExpandOrCollapsedStyle" TargetType="{x:Type ContentPresenter}">
        <Setter Property="ContentTemplate" Value="{DynamicResource Collapsed}"/>
        <Style.Triggers>
            <DataTrigger Binding="{Binding Path=ShowExpanded}" Value="true">
                <Setter Property="ContentTemplate" Value="{DynamicResource Expanded}"/>
            </DataTrigger>
        </Style.Triggers>
    </Style>
    </sap:ActivityDesigner.Resources>
    <Grid>
        <ContentPresenter Style="{DynamicResource ExpandOrCollapsedStyle}" Content="{Binding}" />
    </Grid>

</sap:ActivityDesigner>