SereiesMapping and dateTime

[andrea bellagamba]

Hi I am using a RadChart (version 2010.1.0422.1040) to display 3 series.
Each serie's point is a GraphPoint instance, with a Date and a Value:

public class GraphPoint
  {
    public DateTime Date;
    public double Value;
 
    public GraphPoint(DateTime date, double value)
    {
      this.Date = date;
      this.Value = value;
    }
  }

this is teh code thst defines my chart, the SetData method is called with a list of Traffic object containing valid data:
    
    /// <summary>
    /// Set the traffic data.
    /// </summary>
    /// <param name="traffic">The traffic.</param>
    public void SetData(List<Traffic> traffic)
    {
      this.TrafficChart.ItemsSource = null;     
      this.TrafficChart.SeriesMappings.Clear();
      this.TrafficChart.DefaultView.ChartArea.AxisX.AutoRange = true;
 
      var visitSerie = this.SerieDefinition("Visit");
      var valueSerie = this.SerieDefinition("Value");
 
      visitSerie.CollectionIndex = 0;
      valueSerie.CollectionIndex = 1;
 
      this.TrafficChart.SeriesMappings.Add(visitSerie);
      this.TrafficChart.SeriesMappings.Add(valueSerie);






      var visitData = (from t in traffic select new GraphPoint(t.Date, t.Visits)).ToList();
      var valueData = (from t in traffic select new GraphPoint(t.Date, t.Value)).ToList();
 
      var trafficTimeline = new List<List<GraphPoint>>
      {
        visitData,
        valueData
      };
 
      this.TrafficChart.DefaultView.ChartArea.AxisX.IsDateTime = true;
      this.TrafficChart.DefaultView.ChartArea.AxisX.DefaultLabelFormat = "dd-MMM-yyyy";
 
      this.TrafficChart.ItemsSource = trafficTimeline;
    }
 
    /// <summary>
    /// Series the definition.
    /// </summary>
    /// <param name="serieName">Name of the serie.</param>
    /// <returns>The definition.</returns>
    protected SeriesMapping SerieDefinition(string serieName)
    {
      var seriesMapping = new SeriesMapping
      {
        LegendLabel = serieName,
        SeriesDefinition = new LineSeriesDefinition()
        {
          ShowItemLabels = false,
          ShowItemToolTips = true
        }
      };
 
      seriesMapping.SeriesDefinition.Appearance.StrokeThickness = 2d;
 
      var itemMappingX = new ItemMapping("Date", DataPointMember.XValue);
      var itemMappingY = new ItemMapping("Value", DataPointMember.YValue);      
 
      seriesMapping.ItemMappings.Add(itemMappingX);
      seriesMapping.ItemMappings.Add(itemMappingY);
 
      return seriesMapping;
    }
  }


When assigning the: 

this.TrafficChart.ItemsSource = trafficTimeline;



I get this error:





Invalid cast from 'DateTime' to 'Double'.

















can yuo explain why since I have specified the DefaultView.ChartArea.AxisX.IsDateTime = true;

and mapper the Date property to the XValue

var itemMappingX = new ItemMapping("Date", DataPointMember.XValue);

[Ves]

Hello Andrea,

Binding to fields is not supported. Please, promote the fields in GraphPoint class to properties and you will not experience such issues.

Best regards,
Ves
the Telerik team