How to include an external assembly
In order to include an external assembly (.dll) in UiPath, you have to take the following steps:
1. Create a new Class Library C#/VB project
2. Right click on References ->Add Reference
3. Browse for the external dll and add it as a reference
4. Do the same thing for System.Activities.Presentation, but search for it through to the list of already available assemblies
5. Create a class that implements IRegisterMetadata (from System.Activities.Presentation.Metadata namespace) to make your assembly visible to UiPath. This is not necesary if your assembly has activities.
public class RegisterMetadata : IRegisterMetadata
public void Register()
6. You need to use at least one object from the external assembly to force loading it in UiPath
7. Build the project in Release
8. Follow this article to learn how to create a custom package in which you have to include both the created and the referenced external assemblies.