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Gui.cs - Terminal UI toolkit for .NET

This is a simple UI toolkit for .NET, .NET Core and Mono and works on both Windows and Linux/Unix.

A presentation of this was part of the Retro.NET talk at .NET Conf 2018 Slides

The toolkit contains various controls for building text user interfaces:

• Buttons
• Labels
• Text entry
• Text view
• Time editing field
• Radio buttons
• Checkboxes
• Dialog boxes
  • Message boxes
• Windows
• Menus
• ListViews
• Frames
• ProgressBars
• Scroll views and Scrollbars
• Hexadecimal viewer/editor (HexView)

All visible UI elements are subclasses of the View, and these in turn can contain an arbitrary number of subviews.

It comes with a mainloop to process events, process idle handlers, timers and monitoring file descriptors.

It is designed to work on Curses and the Windows Console, works well on both color and monochrome terminals and has mouse support on terminal emulators that support it.

Documentation

• API documentation for details.

• Overview contains the conceptual documentation and a walkthrough of the core concepts of gui.cs

Sample Usage

using Terminal.Gui;

class Demo {
    static void Main ()
    {
        Application.Init ();
        var top = Application.Top;

	// Creates the top-level window to show
        var win = new Window ("MyApp") {
	    X = 0,
	    Y = 1, // Leave one row for the toplevel menu

	    // By using Dim.Fill(), it will automatically resize without manual intervention
	    Width = Dim.Fill (),
	    Height = Dim.Fill ()
	};
        top.Add (win);

	// Creates a menubar, the item "New" has a help menu.
        var menu = new MenuBar (new MenuBarItem [] {
            new MenuBarItem ("_File", new MenuItem [] {
                new MenuItem ("_New", "Creates new file", NewFile),
                new MenuItem ("_Close", "", () => Close ()),
                new MenuItem ("_Quit", "", () => { if (Quit ()) top.Running = false; })
            }),
            new MenuBarItem ("_Edit", new MenuItem [] {
                new MenuItem ("_Copy", "", null),
                new MenuItem ("C_ut", "", null),
                new MenuItem ("_Paste", "", null)
            })
        });
        top.Add (menu);

	var login = new Label ("Login: ") { X = 3, Y = 2 };
	var password = new Label ("Password: ") {
	    	X = Pos.Left (login),
		Y = Pos.Top (login) + 1
        };
	var loginText = new TextField ("") {
                X = Pos.Right (password),
                Y = Pos.Top (login),
                Width = 40
        };
        var passText = new TextField ("") {
                Secret = true,
                X = Pos.Left (loginText),
                Y = Pos.Top (password),
                Width = Dim.Width (loginText)
        };
	
	// Add some controls, 
	win.Add (
	    // The ones with my favorite layout system
  	    login, password, loginText, passText,

	    // The ones laid out like an australopithecus, with absolute positions:
            new CheckBox (3, 6, "Remember me"),
            new RadioGroup (3, 8, new [] { "_Personal", "_Company" }),
            new Button (3, 14, "Ok"),
            new Button (10, 14, "Cancel"),
            new Label (3, 18, "Press F9 or ESC plus 9 to activate the menubar"));

        Application.Run ();
    }
}

Alternatively, you can encapsulate the app behavior in a new Window-derived class, say App.cs containing the code above, and simplify your Main method to:

using Terminal.Gui;

class Demo {
    static void Main ()
    {
        Application.Run<App> ();
    }
}

The example above shows how to add views, two styles are used, a very nice layout system that I have no name for, but that is documented, and the absolute positioning.

Installing it

If you want to try Gui.cs, use NuGet to install the Terminal.Gui NuGet package:

https://www.nuget.org/packages/Terminal.Gui

Running and Building

You can find a trivial .NET core sample application in the "StandaloneExample" directory. You can execute it by running dotnet run in that directory.

That sample relies on the distributed NuGet package, if you want to to use the code on GitHub, you can open the Example program which references the library built out of this tree.

Input Handling

The input handling of gui.cs is similar in some ways to Emacs and the Midnight Commander, so you can expect some of the special key combinations to be active.

The key ESC can act as an Alt modifier (or Meta in Emacs parlance), to allow input on terminals that do not have an alt key. So to produce the sequence Alt-F, you can press either Alt-F, or ESC followed by the key F.

To enter the key ESC, you can either press ESC and wait 100 milliseconds, or you can press ESC twice.

ESC-0, and ESC-1 through ESC-9 have a special meaning, they map to F10, and F1 to F9 respectively.

Driver model

Currently gui.cs has support for ncurses, System.Console and a full Win32 console front-end.

ncurses is used on Unix with color support based on what your library is compiled with; The windows driver supports full color and mouse, and an easy-to-debug System.Console can be used on Windows and Unix, but lacks mouse support.

You can force the use of System.Console on Unix as well, see Core.cs.

Tasks

There are some tasks in the github issues, and some others are being tracked in the TODO.md file.

History

This is an updated version of gui.cs that I wrote for mono-curses in 2007.

The original gui.cs was a UI toolkit in a single file and tied to curses. This version tries to be console-agnostic and instead of having a container/widget model, only uses Views (which can contain subviews) and changes the rendering model to rely on damage regions instead of burderning each view with the details.

Releases

Recently, I setup VSTS to do the releases, for now, this requires a branch to be pushed with the name release/XXX, do this after the NuGet package version has been updated on the Terminal.Gui/Terminal.Gui.csproj, and push.

Then once the package is built, VSTS will request an approval.