Conversion API

The conversion API that the ChartView provides, allows the conversion of a position on the screen (for example the position of the mouse) to ChartView coordinates.

Using the conversion API

Both RadCartesianChart and RadPolarChart provide a ConvertPointToData method. This method takes a System.Windows.Point as an argument (position on the screen) and returns an object of type DataTuple.

The DataTuple class has two properties: FirstValue and SecondValue, both of type object. In the context of RadCartesianChart they represent the coordinates on the Horizontal and the Vertical axes and in the context of RadPolarChart - the coordinates on the Polar and the Radial axes.

Here is a RadCartesianChart example:

• C#
• VB.NET

private void UIElement_MouseMove(object sender, MouseEventArgs e) 
{ 
    Point mousePosition = e.GetPosition(radCartesianChart1); 
    DataTuple tuple = radCartesianChart1.ConvertPointToData(mousePosition); 
 
    string Category = (string)tuple.FirstValue; 
    double Value = (double)tuple.SecondValue; 
    //... 
} 

Private Sub UIElement_MouseMove(sender As Object, e As MouseEventArgs) 
    Dim mousePosition As Point = e.GetPosition(radCartesianChart1) 
    Dim tuple As DataTuple = radCartesianChart1.ConvertPointToData(mousePosition) 
 
    Dim Category As String = DirectCast(tuple.FirstValue, String) 
    Dim Value As Double = CDbl(tuple.SecondValue) 
    '... 
End Sub 

The RadCartesianChart provides an overloaded version of the ConvertPointToData method, which besides a System.Windows.Point, takes a two other arguments - references to a Horizontal and a Vertical axes. This allows the user to get information relative to the specified axes (often different then the default ones), enabling the use of additional axes.