Value Snapping

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Several objects in the chart object model have the ability to snap to certain values on the scales / axes they are displayed on. These objects include the NRangeSelection, NAxisCursor and NIndicator derived classes.

The value snapping functionality is controlled through an instance of an object deriving from the abstract NValueSnapper class. The following table shows the possible value snapper objects and how they snap values to a chart or gauge axis:

Class	Description
NAxisMajorTickSnapper	Snaps values to the major ticks of the axis
NAxisMinorTickSnapper	Snaps values to the minor ticks of the axis
NAxisRulerClampSnapper	Clamps values to the axis min / max values
NAxisRulerMinMaxSnapper	Snaps values to the axis min / max values
NNumericValueSnapper	Represents a value snapper that snaps values to the nearest step from a specified origin.
NDateTimeValueSnapper	Represents a value snapper that snaps date/time values to the nearest date time step from a specified date/time origin.

The following code shows how to implement a radial gauge with a needle indicator snapping to the nearest value with step 5 – for example 0, 5, 10 etc.

C#	Copy Code
NRadialGaugePanel radialGauge = new NRadialGaugePanel(); NNeedleValueIndicator needleIndicator = new NNeedleValueIndicator(); needleIndicator.ValueSnapper = new NNumericValueSnapper(5); radialGauge.Indicators.Add(needleIndicator); nChartControl1.Panels.Clear(); nChartControl1.Panels.Add(radialGauge); nChartControl1.Controller.Tools.Clear(); nChartControl1.Controller.Tools.Add(new NSelectorTool()); nChartControl1.Controller.Tools.Add(new NIndicatorDragTool());

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NRadialGaugePanel radialGauge = new NRadialGaugePanel();

NNeedleValueIndicator needleIndicator = new NNeedleValueIndicator();
needleIndicator.ValueSnapper = new NNumericValueSnapper(5);
radialGauge.Indicators.Add(needleIndicator);

nChartControl1.Panels.Clear();
nChartControl1.Panels.Add(radialGauge);

nChartControl1.Controller.Tools.Clear();
nChartControl1.Controller.Tools.Add(new NSelectorTool());
nChartControl1.Controller.Tools.Add(new NIndicatorDragTool());

Visual Basic	Copy Code
Dim radialGauge As New NRadialGaugePanel Dim needleIndicator As New NNeedleValueIndicator needleIndicator.ValueSnapper = New NNumericValueSnapper(5) radialGauge.Indicators.Add(needleIndicator) NChartControl1.Panels.Clear() NChartControl1.Panels.Add(radialGauge) NChartControl1.Controller.Tools.Clear() NChartControl1.Controller.Tools.Add(New NSelectorTool) NChartControl1.Controller.Tools.Add(New NIndicatorDragTool)

Visual Basic

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Dim radialGauge As New NRadialGaugePanel

Dim needleIndicator As New NNeedleValueIndicator
needleIndicator.ValueSnapper = New NNumericValueSnapper(5)
radialGauge.Indicators.Add(needleIndicator)

NChartControl1.Panels.Clear()
NChartControl1.Panels.Add(radialGauge)

NChartControl1.Controller.Tools.Clear()
NChartControl1.Controller.Tools.Add(New NSelectorTool)
NChartControl1.Controller.Tools.Add(New NIndicatorDragTool)

Related Examples

Windows Forms: Gauge Gallery \ Gauges \ Interactivity \Dragging Indicators

Windows Forms: Interactivity \ Tools \ Data Cursor Tool