.CLS

.CLS file extension

This is the basic program to work with .CLS extension

Microsoft Visual Basic

Microsoft Visual Basic Visual Basic Class Module

Visual Studio is extensible by nature, ultimately consisting of a core "shell" that implements all commands, windows, editors, project types, languages, and other features through dynamically loadable modules called "packages".[19][20] Microsoft encourages and fosters third party partners to create modules for Visual Studio via the free VSIP program. However, according to Dan Fernandez, Microsoft "made a business decision to not allow 3rd party extensibility in Express"... (more)

The program works with the following extensions: bas, cls, ctl, dob, dsr, frm, pag, vbg, vbp and vbz

.CLS extension is also supported by the following programs:

Microsoft Visual Studio Enterprise Edition

Microsoft Visual Studio Enterprise Edition Visual Basic Class Module

An application development kit with several handy utilities uncluded.
LEd

LEd LaTeX document class file

Visual Basic Professional SP

Visual Basic Professional SP Visual Basic Class Module

Microsoft Visual Studio Professional Edition

Microsoft Visual Studio Professional Edition Visual Basic Class Module

It lets developers create applications across the web, cloud, and devices.
WinEdt

WinEdt LaTeX Class

Edit LaTeX documents, HTML pages, and other text files.
MicroGrade

MicroGrade MySQL Tools for

It is an essential software tool for educators at any grade level.
Grade Machine

Grade Machine Grade Machine Class Document