ChartControl.CalcHitInfo(Point) Method
Returns information on the chart elements located at the specified point.
Namespace: DevExpress.Xpf.Charts
Assembly: DevExpress.Xpf.Charts.v19.1.dll
Declaration
Parameters
Name | Type | Description |
---|---|---|
point | Point | A Point structure which specifies the test point coordinates relative to the chart’s top-left corner. |
Returns
Type | Description |
---|---|
ChartHitInfo | A ChartHitInfo object, which contains information about the chart elements located at the test point. |
Remarks
Use the CalcHitInfo method to determine which element is located at the specified point. For instance, this can be used when handling the chart’s MouseDown event to determine which element was clicked. In such cases, pass the current mouse pointer’s coordinates as the method’s parameter.
Example
This example demonstrates how to display custom information from the underlying datasource in a custom tooltip for every data point.
To accomplish this, it is necessary to handle the chart’s MouseMove event, obtain the current SeriesPoint via the ChartControl.CalcHitInfo method, and if the series point is not null (Nothing in Visual Basic), display a tooltip with its information.
Note that in addition to the MouseMove event, it is also necessary to handle the MouseLeave, to hide the tooltip when the mouse pointer is not over the chart.
If you wish to learn how to use built-in tooltips in your application, see the Tooltip topic.
Note
A complete sample project is available at https://github.com/DevExpress-Examples/how-to-display-custom-tooltips-over-the-data-point-currently-hovered-by-the-mouse-pointer-e1376.
using System.Windows;
using System.Windows.Controls.Primitives;
using System.Windows.Input;
using DevExpress.Xpf.Charts;
namespace DXChartsTooltips {
public partial class Window1 : Window {
public Window1() {
InitializeComponent();
}
private void chartControl1_MouseMove(object sender, MouseEventArgs e) {
ChartHitInfo hitInfo = chartControl1.CalcHitInfo(e.GetPosition(chartControl1));
if (hitInfo != null && hitInfo.SeriesPoint != null) {
SeriesPoint point = hitInfo.SeriesPoint;
tooltip_text.Text = string.Format("Series = {0}\nArgument = {1}\nValue = {2}",
point.Series.DisplayName, point.Argument, point.Value);
tooltip1.Placement = PlacementMode.Mouse;
tooltip1.IsOpen = true;
Cursor = Cursors.Hand;
}
else {
tooltip1.IsOpen = false;
Cursor = Cursors.Arrow;
}
}
private void chartControl1_MouseLeave(object sender, MouseEventArgs e) {
tooltip1.IsOpen = false;
}
}
}
Related GitHub Examples
The following code snippet (auto-collected from DevExpress Examples) contains a reference to the CalcHitInfo(Point) method.
Note
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