Table of Contents

App Extensions - App Code

Extensions can include custom c# code which is either used by the extension itself (e.g. an input-type) or can be used by the App as a whole.

Tip

This allows you to create small libraries of code which solve a specific problem, and then share them across multiple Apps by installing the extension in each App.

Location and Namespace

You should place the code for the extension in /AppCode/Extensions/{ExtensionName}/. The {ExtensionName} should match the folder of the extension itself, as it's used in /extensions/{ExtensionName}/.

Tip

In the main extension in /extensions/, the convention is to use lower-case only, but here we recommend using PascalCase to match C# conventions.

You can also create sub folders and sub-namespaces as needed. Some common sub-folders could be Services, WebApi, Controllers, or Helpers depending on the purpose of the code. For data we recommend Data or Models.

For namespaces you should really use App.Extensions.{ExtensionName} to avoid conflicts with other extensions.

What You Can Build in AppCode

Typical things implemented in extension AppCode:

  • Custom DataSources (for Visual Query and code)
  • WebAPI controllers (endpoints used by the app or UI)
  • Reusable services (API clients, business logic, calculations)
  • Models / DTOs shared across controllers and DataSources
  • Helper utilities used by Razor, APIs, or DataSources

If you only need small helper methods for a single view, keep them in the Razor file. If the logic is reused across multiple views/apps, put it into AppCode.

Special Compiling Options

If you need to ensure special DLLs are referenced during compilation, see App Extensions - Special Compiler Options.

Include in the Package Definition

The package export system only exports parts which have been declared to be in use. So make sure to tick the "App Code" checkbox in the extension's package definition UI.

History

  1. Beta in v20.09, planned stable release in v21.00
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