Interactivity Overview

In This Topic

It is indeed very nice to have a presentation quality chart or text displayed by your .NET application, but often this is not enough to build a really useful program. What you may need sometimes is information passed from the component to the program that drives it.

The nature of this information can vary, but the common in all these actions is that the component is initiating them and the program simply decides whether to respond in some way or just to skip it. Building interactive Web applications is out of the scope of this book although the techniques for applying tooltips and cursors are the same in both cases. For more detailed information on how to generate interactive web content check out the ThinWeb Chart Overview and WebForms Deployment.

Interactivity in Windows Forms is controlled by accessing the NController object exposed from the Controller property of the control:

C#	Copy Code
NController controller = chartControl.Controller;

Visual Basic	Copy Code
Dim controller As NController = chartControl.Controller

The controller has two properties: Selection and Tools that work together when interactivity operations occur.

Selection

The selection object represented by the NSelection class holds the selected elements in the control. It provides the target for interactivity operations. For example when you use data point dragging it will check whether the selection contains a data point and if so it will start to drag it. The following code obtains the selection object from the controller:

C#	Copy Code
NController controller = chartControl.Controller; NSelection selection = controller.Selection;

Visual Basic	Copy Code
Dim controller As NController = chartControl.Controller Dim selection As NSelection = controller.Selection

The selection can be modified both programmatically and by the user.

Tools Collection

The tools collection holds objects derived directly or indirectly from the NTool object. It is accessible through the Tools property of the Controller object:

C#	Copy Code
NController controller = chartControl.Controller; NToolCollection tools = controller.Tools;

Visual Basic	Copy Code
Dim controller As NController = chartControl.Controller Dim tools As NToolCollection = controller.Tools

There are four major tool types as described in the following table:

Tool Type	Description
Selector Tool	Dynamically modifies the selection based on the chart element the mouse is currently over.
Drag Tool	Checks the selection for objects of type it requires and if such objects are present in the selection starts a drag operation when the user presses the left mouse button and drags the mouse.
Interactivity Tool	Checks the InteractivityStyle applied on the chart element the mouse is currently over and performs an action accordingly. For example display tooltip or change the mouse cursor.
Synchronizer Tool	Passes mouse and keyboard input to a chart element. For example mouse down event to an axis scroller.

The following topics show how to work with the Selection and ToolsCollection objects that help you to create highly interactive charts.

Related Examples

Windows forms: Interactivity\Drag Operations; Interactivity\Mouse Events; Interactivity\Tooltips and Cursors

See Also