Base CSS property (Design System Object)

Official Content
This documentation is valid for:
A CSS library to include as a base style.


Bootstrap v3


Objects: Design System
Generators: Java, .NET, .NET Core


The material available online about Web Design to integrate into the applications developed with GeneXus is astonishing! There is a boom of the so-called "CSS Frameworks," which complement JavaScript development Frameworks (for example, JQuery). Applications can be made more attractive thanks to CSS Frameworks.

These CSS Frameworks provide hundreds of widgets, compositions, sources, etc.
Some of the most popular ones are as follows:

  • Bootstrap
  • SemanticUI
  • Pure.css
  • Kube
  • Materialize

What is a Base Library

A Base Library is an external resource that uses a CSS Framework. For example, Semantic UI, Bootstrap, etc.

Base Libraries are external CSS & JS & Assets files that are globally installed with GeneXus.

How to create a new Base Library inside a KB

First, to create a Base Library, compress all the required files (CSS, JS, etc.) into a ZIP file and save it with .gxlibrary extension.

Next, you can include that Base Library in your Knowledge Base by creating a new File object and specifying the path to upload your Base Library (make sure that when adding the file, the name ends with _gxlibrary; otherwise, the IDE will not consider it as a library).

Finally, the Library will be offered for this property so that you can select it.

While several libraries can be included in the KB, using the same Base CSS for different objects is recommended in order to maintain consistency.

Runtime/Design time

This property applies only at design-time.

How to apply changes

To apply the corresponding changes when the property value is configured, Build any object.


This property is available since GeneXus 17 Upgrade 6.