Windows Forms, also known as Winforms, is a free, open-source graphical user interface (GUI) class library for building Windows desktop applications, included as a part of Microsoft .NET, .NET Framework or Mono,[2] providing a platform to write client applications for desktop, laptop, and tablet PCs.

[3] While it is seen as a replacement for the earlier and more complex C++ based Microsoft Foundation Class Library, it does not offer a comparable paradigm[4] and only acts as a platform for the user interface tier in a multi-tier solution.

Unlike a batch program, it spends most of its time simply waiting for the user to do something, such as fill in a text box or click a button.

[9] Windows Forms is similar to Microsoft Foundation Class (MFC) library in developing client applications.

This provides the minimal functionality of a user interface element such as location, size, color, font, text, as well as common events like click and drag/drop.

Many attribute values can be modified during run time based on user actions or changes in the environment, providing a dynamic application.

[15] During a question-and-answer session at the Build 2014 Conference, Microsoft explained that Windows Forms was under maintenance mode, with no new features being added, but bugs found would still be fixed.

[17] For future development, Microsoft has succeeded Windows Forms with an XAML-based GUI entry using frameworks such as WPF and UWP.

Mono is a project led by Xamarin (formerly by Ximian, then Novell) to create an Ecma standard compliant .NET Framework compatible set of tools.