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 interactivity tools like the NRectangleZoomTool and NAxisCursorTool as well as NIndicator derived gauge objects.
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 needle indicator snapping to the nearest value with step 5 – for example 0, 5, 10 etc.
| C# |
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NNeedleValueIndicator needle = new NNeedleValueIndicator(); needle.AllowDragging = true; needle.ValueSnapper = new NNumericValueSnapper(5); radialGauge.Indicators.Add(needle); |
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