Refresh Report Not Calling Chart Need Datasource

[Brant]

I have an interesting situation.  I have a report that has a chart on it.  The web form (ASP.NET) determines what data is going to the chart itself.  In the telerik report I build the chart programmatically based on the data passed in. This means I have to set a public member as a datatable and refresh the report to have the chart recall the need datasource event.  The need datasource event fires off the function that builds the chart.  Now I recreated this in a windows app and it works perfectly.  It just isn't working in the web.  I am using 2012 Q1.  Here is my code to call below:

In Telerik Report:
Public ChartSource As New DataTable

  Private Sub Chart1_NeedDataSource(sender As System.Object, e As System.EventArgs) Handles Chart1.NeedDataSource
        GetSeries(ChartSource)
  End Sub

In ASP.NET VB:
 Dim rpt As New clsQT9Reports.rptCARBarChart()
 rpt.ChartSource = DT1  'this is the chart data
 rpt.DataSource = dt  'this is a single record datatable that literally just loaded the header on the report
 rptVWR.Report = Nothing
 rptVWR.Report = rpt
  rptVWR.RefreshReport() 

[Steve]

Hi Brant,

You have not posted the code for the GetSeries method, where the actual data source assignment is done. Be aware that the NeedDataSource event of the chart would only fire if the chart has no data source set i.e. its DataSource property is empty. If in the GetSeries method you're setting the data source to the chart definition item, then the observed behavior is expected, because after the first iteration, the chart no longer needs a datasource and there is no reason to fire the NeedDataSource event. To avoid that you should either create the chart manually by creating series and series items or use the processing chart object and its DataSource property i.e.:

Private Sub chart1_NeedDataSource(sender As Object, e As EventArgs)
    Dim procChart As Telerik.Reporting.Processing.Chart = DirectCast(sender, Telerik.Reporting.Processing.Chart)
    procChart.DataSource = GetSeries(ChartSource)
End Sub

As per your description, it sounds a better idea to have a DataSource for the chart set via the declarative Data Source Components and only modify the data via DataSourceParameter which comes from the web application. This way the chart would always display relevant data.

Regards,
Steve
the Telerik team

[Brant]

Steve,
Sorry for my delay.  I was out of town.  I don't think that would work with how my sub GetSeries works.  I have attached the code below:

Public Sub GetSeries(_DT As DataTable)
        Dim dt As New DataTable, xValue As Double

        'Dim CN As New SqlClient.SqlConnection(Me.ReportParameters.Item("ConnectionString").Value)
        'Dim CMD As New SqlClient.SqlCommand(Me.ReportParameters.Item("sSQL").Value, CN)

        '      CN.Open()
        'Dim DA As New SqlClient.SqlDataAdapter(CMD)
        '      DA.Fill(dt)
        '      CN.Close()

        dt = _DT


        Chart1.PlotArea.XAxis.AutoScale = False
        Chart1.PlotArea.XAxis.AutoShrink = False


       
        Chart1.Style.BackgroundColor = Color.LightGray
        Chart1.SeriesOrientation = Charting.ChartSeriesOrientation.Horizontal

        'get the column count to determine how many series there are per row
        Dim iCOL As Integer, stSeries As String = ""
        iCOL = dt.Columns.Count


        If dt.Columns.Count > 2 Then
            If Me.ReportParameters.Item("stack").Value = False Then 'do multi series bar chart
                Dim oSeries As Charting.ChartSeries = New Charting.ChartSeries("Open", Charting.ChartSeriesType.Bar)
                Chart1.Series.Add(oSeries)

                Dim rSeries As Charting.ChartSeries = New Charting.ChartSeries("Rejected", Charting.ChartSeriesType.Bar)
                Chart1.Series.Add(rSeries)

                Dim sSeries As Charting.ChartSeries = New Charting.ChartSeries("Submitted", Charting.ChartSeriesType.Bar)
                Chart1.Series.Add(sSeries)

                Dim cSeries As Charting.ChartSeries = New Charting.ChartSeries("Closed", Charting.ChartSeriesType.Bar)
                Chart1.Series.Add(cSeries)
                xValue = -1
                Dim axisItem As Charting.ChartAxisItem

                For i As Integer = 0 To dt.Rows.Count - 1
                    If stSeries <> dt.Rows(i).Item(0).ToString Then
                        xValue = xValue + 1
                        axisItem = New Charting.ChartAxisItem(dt.Rows(i).Item(0).ToString)
                        axisItem.Value = xValue
                        Chart1.PlotArea.XAxis.AddItem(axisItem)
                        stSeries = dt.Rows(i).Item(0).ToString
                    End If

                    Select Case dt.Rows(i).Item(1)
                        Case Is = 1
                            Dim seriesItem As New Telerik.Reporting.Charting.ChartSeriesItem
                            seriesItem.YValue = dt.Rows(i).Item(iCOL - 1)
                            seriesItem.XValue = xValue
                            seriesItem.Appearance.FillStyle.SecondColor = Color.DarkRed
                            seriesItem.Appearance.FillStyle.MainColor = Color.Red
                            seriesItem.Name = dt.Rows(i).Item(0).ToString
                            oSeries.AddItem(seriesItem)
                        Case Is = 2
                            Dim seriesItem As New Telerik.Reporting.Charting.ChartSeriesItem
                            seriesItem.YValue = dt.Rows(i).Item(iCOL - 1)
                            seriesItem.XValue = xValue
                            seriesItem.Appearance.FillStyle.SecondColor = Color.Orange
                            seriesItem.Appearance.FillStyle.MainColor = Color.DarkOrange
                            seriesItem.Name = dt.Rows(i).Item(0).ToString
                            rSeries.AddItem(seriesItem)
                        Case Is = 3
                            Dim seriesItem As New Telerik.Reporting.Charting.ChartSeriesItem
                            seriesItem.YValue = dt.Rows(i).Item(iCOL - 1)
                            seriesItem.XValue = xValue
                            seriesItem.Appearance.FillStyle.SecondColor = Color.Blue
                            seriesItem.Appearance.FillStyle.MainColor = Color.DarkBlue
                            seriesItem.Name = dt.Rows(i).Item(0).ToString
                            sSeries.AddItem(seriesItem)
                        Case Is = 4
                            Dim seriesItem As New Telerik.Reporting.Charting.ChartSeriesItem
                            seriesItem.YValue = dt.Rows(i).Item(iCOL - 1)
                            seriesItem.XValue = xValue
                            seriesItem.Appearance.FillStyle.SecondColor = Color.DarkGreen
                            seriesItem.Appearance.FillStyle.MainColor = Color.LightGreen
                            seriesItem.Name = dt.Rows(i).Item(0).ToString
                            cSeries.AddItem(seriesItem)
                    End Select


                Next

            Else 'do stacked bar chart
                Dim oSeries As Charting.ChartSeries = New Charting.ChartSeries("Open", Charting.ChartSeriesType.StackedBar)
                Dim rSeries As Charting.ChartSeries = New Charting.ChartSeries("Rejected", Charting.ChartSeriesType.StackedBar)
                Dim sSeries As Charting.ChartSeries = New Charting.ChartSeries("Submitted", Charting.ChartSeriesType.StackedBar)


                Dim cSeries As Charting.ChartSeries = New Charting.ChartSeries("Closed", Charting.ChartSeriesType.StackedBar)

                stSeries = ""
                xValue = -1
                Dim axisItem As Charting.ChartAxisItem

                For i As Integer = 0 To dt.Rows.Count - 1
                    If stSeries <> dt.Rows(i).Item(0).ToString Then
                        xValue = xValue + 1
                        axisItem = New Charting.ChartAxisItem(dt.Rows(i).Item(0).ToString)
                        axisItem.Value = xValue
                        Chart1.PlotArea.XAxis.AddItem(axisItem)
                        stSeries = dt.Rows(i).Item(0).ToString
                    End If
                    Select Case dt.Rows(i).Item(1)
                        Case Is = 1
                            Dim seriesItem As New Telerik.Reporting.Charting.ChartSeriesItem
                            seriesItem.YValue = dt.Rows(i).Item(iCOL - 1)
                            seriesItem.XValue = xValue
                            seriesItem.Appearance.FillStyle.SecondColor = Color.DarkRed
                            seriesItem.Appearance.FillStyle.MainColor = Color.Red
                            seriesItem.Name = dt.Rows(i).Item(0).ToString
                            oSeries.AddItem(seriesItem)
                        Case Is = 2
                            Dim seriesItem As New Telerik.Reporting.Charting.ChartSeriesItem
                            seriesItem.YValue = dt.Rows(i).Item(iCOL - 1)
                            seriesItem.XValue = xValue
                            seriesItem.Appearance.FillStyle.SecondColor = Color.DarkGoldenrod
                            seriesItem.Appearance.FillStyle.MainColor = Color.Goldenrod
                            seriesItem.Name = dt.Rows(i).Item(0).ToString
                            rSeries.AddItem(seriesItem)
                        Case Is = 3
                            Dim seriesItem As New Telerik.Reporting.Charting.ChartSeriesItem
                            seriesItem.YValue = dt.Rows(i).Item(iCOL - 1)
                            seriesItem.XValue = xValue
                            seriesItem.Appearance.FillStyle.SecondColor = Color.DarkBlue
                            seriesItem.Appearance.FillStyle.MainColor = Color.Blue
                            seriesItem.Name = dt.Rows(i).Item(0).ToString
                            sSeries.AddItem(seriesItem)
                        Case Is = 4
                            Dim seriesItem As New Telerik.Reporting.Charting.ChartSeriesItem
                            seriesItem.YValue = dt.Rows(i).Item(iCOL - 1)
                            seriesItem.XValue = xValue
                            seriesItem.Appearance.FillStyle.SecondColor = Color.DarkGreen
                            seriesItem.Appearance.FillStyle.MainColor = Color.LightGreen
                            seriesItem.Name = dt.Rows(i).Item(0).ToString
                            cSeries.AddItem(seriesItem)
                    End Select


                Next
                Chart1.PlotArea.XAxis.AutoScale = False

                Chart1.Series.Add(oSeries)
                Chart1.Series.Add(rSeries)
                Chart1.Series.Add(sSeries)
                Chart1.Series.Add(cSeries)
            End If
        Else
            Dim cSeries As New Telerik.Reporting.Charting.ChartSeries
            cSeries.Name = "CorrectiveActions"
            stSeries = cSeries.Name
            cSeries.Type = Charting.ChartSeriesType.Bar

            For i As Integer = 0 To dt.Rows.Count - 1
                Dim seriesItem As New Telerik.Reporting.Charting.ChartSeriesItem
                seriesItem.YValue = dt.Rows(i).Item(1)
                seriesItem.Appearance.FillStyle.SecondColor = Color.Red
                seriesItem.Appearance.FillStyle.MainColor = Color.DarkRed
                seriesItem.Name = dt.Rows(i).Item(0).ToString
                cSeries.AddItem(seriesItem)

                Chart1.PlotArea.XAxis.AddItem(dt.Rows(i).Item(0).ToString)
            Next

            cSeries.Appearance.TextAppearance.TextProperties.Color = Color.DarkBlue
            Chart1.Series.Add(cSeries)

        End If


        If dt.Columns.Count > 2 Then
            Chart1.Legend.Visible = True
            Dim CARColors(3) As Color
            CARColors(0) = Color.Red
            CARColors(1) = Color.Orange
            CARColors(2) = Color.Green
            CARColors(3) = Color.Blue
            Dim seriesP As Charting.Palette = New Charting.Palette("CAR", CARColors, CARColors)
            Chart1.CustomPalettes.Add(seriesP)
            Chart1.SeriesPalette = "CAR"

        Else
            Chart1.Legend.Visible = False
        End If


        Chart1.PlotArea.XAxis.AxisLabel.TextBlock.Text = Me.ReportParameters.Item("Xaxis").Value
        Chart1.PlotArea.XAxis.AxisLabel.Visible = True
        Chart1.PlotArea.YAxis.AxisLabel.TextBlock.Text = Me.ReportParameters.Item("Yaxis").Value
        Chart1.PlotArea.YAxis.AxisLabel.Visible = True
        Chart1.ChartTitle.TextBlock.Text = Me.ReportParameters.Item("header").Value
        Chart1.ImageFormat = System.Drawing.Imaging.ImageFormat.Png


    End Sub

[Steve]

Hi Brant,

Thanks for the code, we see now that you customize the chart item, so that you cannot accomplish this with direct binding to a data source component. Also we see that you do not set DataSource to the chart definition or processing counterpart, so that could not be the problem either.

The only thing left that I can think of is if you are using an out-proc session for your web application. In such case, to utilize the events of the chart item (NeedDataSource, ItemDataBinding, ItemDataBound) you have to attach them in the ItemDataBinding event of the Report. For example:

Private Sub Report1_ItemDataBinding(sender As System.Object, e As System.EventArgs) Handles MyBase.ItemDataBinding
    Dim processingReport = DirectCast(sender, Telerik.Reporting.Processing.Report)
    Dim reportDef = DirectCast(processingReport.ItemDefinition, Telerik.Reporting.Report)
    Dim chart As Telerik.Reporting.Chart = DirectCast(reportDef.Items.Find("Chart1", True)(0), Telerik.Reporting.Chart)
    AddHandler chart.NeedDataSource, AddressOf Chart1_NeedDataSource

End Sub

Private Sub Chart1_NeedDataSource(sender As System.Object, e As System.EventArgs)
    Dim processingChart = DirectCast(sender, Telerik.Reporting.Processing.Chart)
    Dim chartDef = DirectCast(sender, Telerik.Reporting.Chart)

    ' ...

End Sub

Regards,
Steve
the Telerik team