Reproducing Incident Form Elements in a Custom Class

Question

Hello again everyone,
I am trying to rollout a completely separate module in SCSM to record MACD (Move/Add/Change/Delete) requests. I decided to use the OOB incident module as my base class as it already contained many fields I require (I inherited the properties
and relationships) and created a new form assembly in Visual Studio to wire the properties to.
After created the form and labels, I imported the .dll into the Authoring Tool so I can just drag out each property from the MP explorer onto the form. Everything works except for the last few fields which are a bit more complex than a standard list or textbox.
I cannot seem to add the controls for the more complicated items like "Affected Services" or "Affected Items", when I try to drag them out to the form I get an error saying cardinality is not set to 1... I am guessing this is because
its trying to map a relationship between a workitem and a service instead of my custom class and a service...
So I went back into Visual Studio and added a ListView to the form, thinking I will have to wire the data bindings inside the form itself. However, I am stuck as I am not sure where "Services" are being written to, as I will need this location
to reference in my empty ListView. I have provided my code and commented where I believe I am missing logic. Thank you in advance for any help!
Note: "servicerelatestoworkitem" is not actually an object, my logic is conceptual and I still have not found which class/object the list of services is being written to.
C# Code containing button logic (an add button to add a service to the ListView, and a delete button to remove a service from the ListView.
private void add_services_button_Click(object sender, RoutedEventArgs e)
   // Open list of Services here, allow user to pick a service, then add selected service to "servicerelatestoworkitem"
   // AffectedServicesListView is populated from servicerelatestoworkitem
private void del_services_button_Click(object sender, RoutedEventArgs e)
    // Test to see if item is being selected and display selected item to confirm ability to manipulate variable
    try
        var itemSelected = ListView.GetIsSelected(AffectedServicesListView);
        MessageBox.Show(itemSelected.ToString());
    catch (Exception ex)
        MessageBox.Show(ex.Message);
    // Remove selected item from servicerelatestoworkitem and refresh AffectedServicesListView
XAML Code containing the list view and two buttons: (Note: The binding is most likely incorrect, I was just experimenting with it)
<ListView x:Name="AffectedServicesListView" HorizontalAlignment="Left" Height="95" Margin="10,414.6,0,0" VerticalAlignment="Top" Width="521" ItemsSource="{Binding Path=AffectedServicesListView, Mode=Default, UpdateSourceTrigger=PropertyChanged}">
                        <ListView.View>
                            <GridView>
                                <GridViewColumn/>
                            </GridView>
                        </ListView.View>
                    </ListView>
                    <Button x:Name="add_services_button" Content="" HorizontalAlignment="Left" Margin="470.55,382.749,0,0" VerticalAlignment="Top" Width="27.674" Height="26.851" Click="add_services_button_Click" BorderBrush="{x:Null}">
                        <Button.Background>
                            <ImageBrush ImageSource="add.png"/>
                        </Button.Background>
                    </Button>
                    <Button x:Name="del_services_button" Content="" HorizontalAlignment="Left" Margin="503.224,382.749,0,0" VerticalAlignment="Top" Width="27.776" Height="26.851" Click="del_services_button_Click" BorderBrush="{x:Null}">
                        <Button.Background>
                            <ImageBrush ImageSource="delete.png"/>
                        </Button.Background>
                    </Button>

Answer 1

Cardinality is a property of relationships classes, not a property of specific relationships. each type of relationship has it's own cardinality values, but the engine only really recognizes "one" and "many". it makes sense to say that
the "affected user" relationship is many to one, because Each work item can have one and only one affected user, but each users may be the affected user of many work items. The Related work items relationship is a many to many, because each workitem
may be related to many other work items. it doesn't make sense to say this specific relationship between this IR and that user is "many to one", because each instance is only between one specific object and another specific objects. the cardinality
just controls how many of those specific relationships instances can exist for each type of relationship. 
There are no out of the box controls for many to many relationships. the Instance Picker control is designed to support one to one and many to one relationships. you'd have to write your own controls for support many to one relationships. Consider Travis
Wright's SR Example for 2010, since most of this code should execute in 2012 and 2012r2 with only minor modifications. 
You'd have to either find the control that defines it, like with the history tab, or recreate it using the
authoring tool or
Visual Studio.