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Multiple external systems

Shows how to configure multiple external systems for Optimizely Forms.



Optimizely Forms is only supported by MVC-based websites and HTML5-compliant browsers.

From version 4.18.0, Optimizely Forms can support multiple external systems. Editors can choose one of the registered systems as a connected data source in the user interface.


To make Optimizely Forms support multiple Marketing Automation connectors:

  1. Create an instance of IExternalSystem and register this with Forms.

    var efmService = ServiceLocator.Current.GetInstance<ExternalSystemService>();
    var custom1 = new CustomExternalSystem("Custom_1");
    custom1.Datasources = GetSomeDatasources(custom1);
    var custom2 = new CustomExternalSystem("Custom_2");
    custom2.Datasources = GetSomeDatasources(custom2);
  2. Forms automatically activates ExternalSystem with the default constructor and registers this with Forms. You can override this default behavior.

  3. Allow the display name of the ExternalSystem by ID. You can get the DisplayName localization resource from the XML path:


    If that resource does not exist, fallback to the default one (like previous versions):


API changes from version 4.18.0

  1. A service, ExternalSystemService, is introduced for working with external systems:
    • WorkingExternalSystem – Get currently activated external systems.
    • HasExternalSystems() – Determine whether there is any implementation of IExternalSystem.
    • ActivateFromTypes() – Automatically try to create instances of IExternalSystem by scanning the assembly. This requires the default constructor of the ExternalSystem. If you do not want to activate your automaticallyExternalSystem, override this method and do nothing or do not provide the default constructor for the ExternalSystem.
    • RegisterExternalSystem – Explicitly register an ExternalSystem. Each ExernalSystem must have a unique ID. The ID should not contain spaces or special characters.
    • UnregisterExternalSystem – Remove an ExternalSystem.
    • GetExternalSystem – Return instance of an ExternalSystem by ID.
    • GetAllExternalSystems – Return instances of ExternalSystem (activated, registered)
  2. The property IPostSubmissionActor.ActiveExternalFieldMappingTable was obsoleted because the Actors should not know about the mappings. If you want to have a mapping table in Actors, you can use IExternalFieldMappingService.GetActiveFieldMappingTables to retrieve them.