NodeEditorGUILayout.InstancePortList

Draw an editable list of instance ports. Port names are named as "[fieldName] [index]"

public static void InstancePortList(string fieldName, Type type, SerializedObject serializedObject, NodePort.IO io, XNode.Node.ConnectionType connectionType = XNode.Node.ConnectionType.Multiple);

Parameters	Summary
fieldName	Base fieldName of the instance ports. If points to the field name of a list, the list will be used as backing values.
type	Instance NodePort value type.
serializedObject	The serializedObject of the node.
io	Whether this list creates inputs or outputs
connectionType	Connection type of added instance ports

// ExampleNode.cs

public class ExampleNode : Node {
    // We will display the list through custom editor, so hide it from the default editor
    [HideInInspector] public List<int> choices;
    
    public override object GetValue(NodePort port) {
        // The instance ports created this way will use the list fieldName and index number, separated by space
        if (port.fieldName.StartsWith("choices ")) {
            int index = int.Parse(port.fieldName.Split(' ')[1]);
            return choices[index];
        }
        return null;
    }
}

// Editor/ExampleNodeEditor.cs

[CustomNodeEditor(typeof(ExampleNode))]
public class ExampleNodeEditor : NodeEditor {
    public override void OnBodyGUI() {
        // Draw default editor first
        base.OnBodyGUI();
        // Draw list with instance ports
        NodeEditorGUILayout.InstancePortList("choices", typeof(int), serializedObject, NodePort.IO.Output);
    }
}

See also: AddInstancePort, RemoveInstancePort