Just as Microsoft provides a native desktop UI toolkit called Windows Forms that ships with Microsoft .NET, the Mono project provides a compatible implementation of this same API, making it possible to build Windows Forms-based applications that run under a variety of operating systems.
| Author's Note: When this article was written, Mono's implementation of Windows Forms had not yet been finalized (see this blog to view the current status of the project). |
Even though Mono's Windows Forms implementation is not yet feature-complete you can use Mono to build robust desktop applications today by choosing an alternative API (see Table 1).
Table 1. A Survey of .NET desktop APIs: The table shows some of the APIs available for building desktop applications with Mono.
.NET Desktop
GUI API |
Description |
| Gtk# |
Gtk# is considered the "native" GUI toolkit that ships with the Mono platform. |
| Glade# |
Glade# is an extension to Gtk#. Beyond adding several useful widgets, GUIs built using Glade# can be described via XML and bound to a runtime object model. |
| Cocoa# |
Cocoa# is a managed wrapper around the native Mac OS X cocoa API. |
| wx.NET |
Wx.NET is a wrapper around the platform-independent wx toolkit. A (major) benefit of Wx.NET is that it maintains the correct look-and-feel of the host OS (including Mac OS X). |
This article introduces you to a very popular .NET GUI alternative named
Gtk#. As you would expect from a modern-day desktop API, Gtk# provides a very rich fabric for building desktop applications. I'll discuss the following core topics:
- Building main windows
- Working with widgets
- Creating menu systems
- Understanding the role of HBox and VBox types
- Creating and using dialog boxes
| Author's Note: This article assumes that you're comfortable with C# and working with the .NET type system (classes, interfaces, enumerations, structures and delegates). |
Getting to Know Gtk#
Gtk# is a managed wrapper around a Linux-centric API termed
Gtk+. Gtk+ is a toolkit originally created to build the popular image processing application
GIMP (the GNU Image Manipulation Program), which explains the origin of the acronym 'Gtk': GIMP Tool Kit.
Although Gtk+ was originally developed for use on Unix/Linux, this API has been ported to numerous operating systems (Win32, Mac OX X, etc). Given the connection between Gtk# and Gtk+, it should come as no surprise that you can use Gtk# to build platform-independent user interfaces on any operating system that supports Gtk+.
Structurally, Gtk# consists of a set of .NET assemblies deployed to the Mono Global Assembly Cache. Table 2 defines the role of the core Gtk# assemblies.
Table 2. The Core Gtk# Assemblies: The table lists the most important Gtk# assemblies and a description of each.
| Gtk# Assembly |
Description |
| gtk-sharp.dll |
Defines the core UI .NET bindings to Gtk+. |
| glib-sharp.dll |
Defines additional (non-UI) .NET bindings to Gtk+. |
| pango-sharp.dll |
Provides binding to the Pango API, used to format and internationalize textual data. |
| atk-sharp.dll |
Binding for the atk accessibility API. |
| gdk-sharp.dll |
Defines numerous low-level rendering APIs. |
| glade-sharp.dll |
Provides support for Glade development with Gtk#. |
| art-sharp.dll |
A vector rending library. |
| rsvg-sharp.dll |
A SVG rendering library. |
 | |
| Figure 1: The MonoDoc UI: MonoDoc Provides Solid Documentation for Gtk#. |
The Mono installation automatically deploys the Gtk# assemblies to the Mono GAC when you install the Mono platform on a Windows or Linux-based OS. Do be aware that installing Gtk# on Mac OS X is a bit more involved. Interested individuals can find OS X installation instructions here.
While this article will in no way attempt to dive into the details of every type found within each Gtk# assembly, you'll find the API is well documented in the MonoDoc utility (see Figure 1).
A Survey of Gtk# Development Options
In this article you'll see how to build several Gtk# applications at the command line using the Mono C# compiler (gmcs) and your text editor of choice. I realize that this is not the visual GUI-building process you may be used to in Visual Studio, but bear with me—this approach is ideal from a learning point of view. Rest assured that if you are serious about building Gtk# user interfaces, several Mono-aware IDEs provide design time assistance. Table 3 documents several possibilities.
Table 3. Mono-Aware IDEs: The table lists several IDEs that offer visual design support for Gtk# development.
| .NET Desktop UI Technology |
Description |
| #develop |
SharpDevelop 2.0 provides Gtk# and Glade# project templates, however it currently lacks visual designer support. |
| MonoDevelop |
Provides a variety of visual tools for building Gtk# / Glade# projects. |
| X-Develop |
Provides a variety of visual tools for building Gtk# / Glade# projects. |
In addition to the IDEs in Table 3, it is possible to build Gtk# applications using Visual Studio 2005 (as well as earlier editions of the product). Check out the following
blog for more information.
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