GoDiagram for Microsoft .NET Concepts

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"We found the GoDiagram tools to be extremely powerful, flexible, and easy to use."
Joey Runyans
Senior Software Engineer
Aegis Technologies Group

GoDiagram Concepts

GoDiagram Concepts

The GoDiagram library, Northwoods.Go, is a set of controls and classes built on the .NET platform. GoDiagram makes it easy to deliver editors that allow users to see and manipulate diagrams of two-dimensional graphical objects arranged in a scrollable window.

GoDiagram provides a variety of basic graphical objects such as rectangles, ellipses, polygons, text, images, and lines. You can group objects together to form more complex objects. You can customize their appearances and behaviors by setting properties and overriding methods.

GoDiagram View

A GoDiagram view is a control that displays a GoDiagram document. It supports mouse-based object manipulation, including selecting, resizing, moving and copying using drag-and-drop. GoDiagram organizes input behaviors into tools that you can modify, override, or add or remove from a view. The view also supports in-place editing, printing, and grids.

GoDiagram Document

A GoDiagram document implements a model that supports manipulation of objects. Adding an object to the document makes it visible in the document's views. You can organize objects in layers. GoDiagram provides support for composing and manipulating graphs (node & arc diagrams), where nodes have ports that are connected by links.

Flexibility and Extensibility

The GoDiagram library is flexible and extensible. Predefined node classes make it easy to build many kinds of graphs. You can easily customize most objects for application-specific purposes by setting properties or by subclassing. You can add completely new graphical objects to the existing framework.

AutoLayout

To provide greater customizability and ease of use, Northwoods offers, as a separate option, another library, Northwoods.Go.Layout. This option extends GoDiagram by providing sophisticated automatic layout algorithms for nodes in graphs. The AutoLayout component is sold and documented separately.

A True .NET component

GoDiagram is written entirely in C#. It only depends on the standard .NET Framework classes and does not explicitly call any external functions.

Why GoDiagram is better than an ActiveX control

Using an ActiveX control rather than a .NET control results in broad, systemic differences in the architecture, interfaces, extensibility, and usability in the .NET environment, both at design time as well as at run time.

ActiveX controls are less safe (implemented in unmanaged code)
ActiveX controls are slower (requires frequent transitions to unmanaged code)
Typical ActiveX controls are not as extensible as GoDiagram (not organized as classes you can inherit from and call in a type-safe manner)
ActiveX controls require other large DLLs to run (large downloads for browser apps)
ActiveX controls do not offer a model-view-controller architecture
Can't have multiple views displaying one document in different ways, such as with different scales or greeking
Can't define new kinds of behaviors and swap and share them among views

Sample Program

Here is the full VB.NET source code to MinimalApp. The screenshot shows how the MinimalApp appears after selecting the two initial nodes, drag-copying them, moving them, creating links between some of them, and then renaming a blue one to “blue” and a magenta one to “magenta”.

Visual Basic:

Public Class MinimalApp

Inherits Form ' constructor Public Sub New()

MyBase.New() Me.Text = "Minimal GoDiagram app" ' create a Go view (a Control) and add to the form Dim myView As GoView = New GoView() myView.Dock = DockStyle.Fill Me.Controls.Add(myView) ' create two nodes for fun... Dim node1 As GoBasicNode = New GoBasicNode() ' specify position, label and color node1.Location = New PointF(100, 100) node1.Text = "first" node1.Editable = True ' first node is editable with F2 only node1.Brush = Brushes.Blue ' add to the document, not to the view myView.Document.Add(node1) Dim node2 As GoBasicNode = New GoBasicNode() node2.Location = New PointF(200, 100) node2.Text = "second" node2.Label.Editable = True ' editable by clicking only node2.Brush = Brushes.Magenta myView.Document.Add(node2)

End Sub Shared Sub Main()

Application.Run(New MinimalApp())

End Sub

End Class

The full documentation to GoDiagram is provided in the evaluation kit.