Drill Down ToolTip Shows Previous WCF Results

[Drew]

Hi,

I have created a LineSeries chart which displays a series of Student results. The ToolTip for each result should then show a Drill Down Chart of more detailed results. All the data is called from a WCF service.

The issue I have is the Drill Down chart is showing the results from the previous WCF Result.
i.e. I hover over Student A and no data is shown. I then hover over Student B and Student A's results are shown.

Here is my Code:

Private Sub ChartArea_ItemToolTipOpening(ByVal tooltip As ItemToolTip2D, ByVal e As ItemToolTipEventArgs)
   mService.GetStudentResultsAsync(e.DataSeries.LegendLabel)
    tooltip.Content = GetDetailBorder()
End Sub

Private Sub mService_GetStudentResultsCompleted(ByVal sender As Object, ByVal e As ServiceReference1.GetStudentResultsCompletedEventArgs) Handles mService.GetStudentResultsCompleted
    Me.DetailChart = New RadChart()

    DetailChart.Background = New SolidColorBrush(Colors.Transparent)
   DetailChart.DefaultView.ChartLegend.Visibility = Windows.Visibility.Collapsed
    DetailChart.Width = 300
    DetailChart.Height = 300

    Dim Definition As ISeriesDefinition = New LineSeriesDefinition() With {.LegendDisplayMode = LegendDisplayMode.DataPointLabel, .ShowItemLabels = True, .ShowItemToolTips = True}
    Dim Mapping As New SeriesMapping() With {.SeriesDefinition = Definition}

    Mapping.ItemMappings.Add(New ItemMapping() With {.DataPointMember = DataPointMember.XCategory, .FieldName = "ResultsName"})
    Mapping.ItemMappings.Add(New ItemMapping() With {.DataPointMember = DataPointMember.YValue, .FieldName = "Cost"})

    DetailChart.SeriesMappings.Add(Mapping)

    For Each Test In e.Result
        Dim LineSeries As New DataSeries()

        Dim LineDefinition As SeriesDefinition = New LineSeriesDefinition()
        LineDefinition.ShowItemLabels = False
        LineDefinition.ShowItemToolTips = True
        LineDefinition.Appearance.PointMark.Shape = MarkerShape.Diamond
        Definition.AnimationSettings = New AnimationSettings() With {.ItemAnimationDuration = New TimeSpan(0, 0, 0, 0, 0)}
        LineSeries.Definition = Definition

        If Not Test.Result2008 = 0 Then LineSeries.Add(New DataPoint(Test.Result2008))
        If Not Test.Result2009 = 0 Then LineSeries.Add(New DataPoint(Test.Result2009))
        If Not Test.Result2010 = 0 Then LineSeries.Add(New DataPoint(Test.Result2010))

        Me.DetailChart.DefaultView.ChartArea.DataSeries.Add(LineSeries)
    Next
End Sub

Private Function GetDetailBorder() As Border
    Dim NewBorder As New Border() With {.Background = DetailChart.Background, .BorderBrush = New SolidColorBrush(Colors.Blue), .BorderThickness = New Thickness(1), .CornerRadius = New CornerRadius(20), .Padding = New Thickness(5)}
    NewBorder.Child = DetailChart

    Return NewBorder
End Function

Help would really be appreciated.

[Velin]

Hello Drew,

Here is the reason for this behavior - you are asynchronously calling the web service within the ItemTooltipOpening event handler and immediately after that you try to show the data. At this time the web service call has not returned so the item tooltip is empty. The same happens again when the tooltip is shown for the second time. This time, however, the first web service call has completed and the data from the first call is shown. You can verify that this is the case if you set a break point in both the mService_GetStudentResultsCompleted and GetDetailBorder functions and you will be able to see the order these methods are executed.

Hope this will help.

Best wishes,
Ryan
the Telerik team