Now that you have gone through the Activity Creation tutorial and have a working activity package, it's time to understand what all the constituent files do and how they interweave to form a UiPath activity. Each activity solution in Visual Studio contains 3 main sections (called projects): the Auxiliary, Activities, and Designers.
The first project contains all the custom classes in the activity namespace and which are referenced in the subsequent projects. These can include clients, custom datatypes, interfaces, exceptions, enums, auxiliary classes, etc. Because these are supporting files that may not exist in your particular activity, the Auxiliary project is optional.
This project contains the execution logic for each activity. Notice that each of your activities in UiPath Studio has a corresponding file in Visual Studio. To understand each of these files, see the Customizing Activities section.
This project contains all the UI elements for your activities, including custom controls, themes (for adding skins and styles), converters (classes used to bind properties and data to UI elements), and the activity UIs. Notice that each activity in UiPath Studio has a corresponding Xaml and Xaml.cs file in Visual Studio.
Also included here are the package's metadata files: DesignerMetadata and the nuspec. More on those in the Building Your Package section.
Notice the Shared folder below the other projects. This is a basket of handy classes and controls that can be used to speed up development. In fact, some are already incorporated into the projects you generated.
Updated about a year ago