Binding Issue

[Trude]

Let's say I have a simple class like this:

Public Class MyBaseClass
    Implements INotifyPropertyChanged
    Private _coord As Integer

    Public Property coord() As Integer
        Get
            coord = _coord
        End Get
        Set(ByVal value As Integer)
            _coord = value
            RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs("coord"))
        End Set
    End Property

    Public Event PropertyChanged(ByVal sender As Object, ByVal e As System.ComponentModel.PropertyChangedEventArgs) Implements System.ComponentModel.INotifyPropertyChanged.PropertyChanged
End Class

I then have a class that essientially contains pointers to entities in the base class:

Public Class MyClass

    Public Property coord_x As MyBaseClass
    Public Property coord_y As MyBaseClass

End Class

Lastly I create an ObervableCollection of MyClass and my XAML looks like this:

.....
<telerik:SeriesMapping.ItemMappings>
    <telerik:ItemMapping DataPointMember="XValue" FieldName="coord_x.value"/>
    <telerik:ItemMapping DataPointMember="YValue" FieldName="coord_y.value"/>
</telerik:SeriesMapping.ItemMappings>
.....

<TextBlock Text="{Binding coord_a.value}"/>

When entities change in the base class the changes are reflected in the TextBlock, but not in the radchart (if I rebind the chart is updated). If the chart is attached directly to the base class (for testing purposes) all changes are reflected in the chart also.

Are there some limitations in your current implementation of radchart or is this a bug?

[Dwight]

Hi Jorn,

The base class does not have property named value, but one named coord. Binding should look like this:

<telerik:SeriesMapping.ItemMappings>
    <telerik:ItemMapping DataPointMember="XValue" FieldName="coord_x.coord"/>
    <telerik:ItemMapping DataPointMember="YValue" FieldName="coord_y.coord"/>
</telerik:SeriesMapping.ItemMappings>

Best wishes,
Joshua
the Telerik team

[Trude]

Sorry, for the late reply. This was a typo on my behalf - of course it should be .coord instead of .value in the XAML code.
Anyway; the problem persists and the code is not working as I expect it to. The textblock updates dynamically, but the chart is not (I have to rebind it manually).

[Evgenia]

Hello Jorn,

As you mentioned "If the chart is attached directly to the base class (for testing purposes) all changes are reflected in the chart also." Current version of RadChart doesn't provide item property changed notification so you should Rebind the Chart in order to have it updated. 
I hope this information helps.

Sincerely yours,
Evgenia
the Telerik team

[kjellerik]

Hi,

I have a problem similar to the one described. It started when i upgraded to telerik controls Q2 (2010.2.924) from version 2010.2.714.1040. The RadChart lost it capabilities to update when i use NotifyPropertyChanged, as it has before. 

<telerikChart:RadChart ItemsSource="{Binding KPIChartEntities}" x:Name="radChart" Grid.Column="1" Grid.Row="1" Margin="15,15,15,0" >
                <telerikChart:RadChart.DefaultView>
                    <charting:ChartDefaultView>
                        <charting:ChartDefaultView.ChartArea>
                            <charting:ChartArea x:Name="mainChart" EnableAnimations="False" EnableStripLinesAnimation="False" >
                                <charting:ChartArea.Annotations>
                                    <charting:CustomGridLine YIntercept="{Binding Target}"
                                                         Visibility="Visible"
                                                         Stroke="Red"
                                                         StrokeThickness="3" />
                                </charting:ChartArea.Annotations>
                                <charting:ChartArea.AxisX>
                                    <charting:AxisX  LabelRotationAngle="90">
                                    </charting:AxisX>
                                </charting:ChartArea.AxisX>
                                <charting:ChartArea.AxisY>
                                    <charting:AxisY Title="{Binding UnitName}">
                                    </charting:AxisY>
                                </charting:ChartArea.AxisY>
                            </charting:ChartArea>
                        </charting:ChartDefaultView.ChartArea>
                    </charting:ChartDefaultView>
                </telerikChart:RadChart.DefaultView>

                <telerikChart:RadChart.SeriesMappings>
                    <charting:SeriesMapping ChartAreaName="mainChart" x:Name="seriesMapping">
                        <charting:SeriesMapping.ItemMappings>
                            <charting:ItemMapping DataPointMember="XCategory" FieldName="XSubCategory" />
                            <charting:ItemMapping DataPointMember="YValue"  FieldName="YValue" />
                        </charting:SeriesMapping.ItemMappings>
                    </charting:SeriesMapping>
                </telerikChart:RadChart.SeriesMappings>
            </telerikChart:RadChart>

The KPIChartEntities is an ObservableCollection<KPIChartEntity>. KPIChartEntity contains a "void UpdateActual()" which updates a the YValue, and runs a NotifyPropertyChanged to get reflected in the chart. 

public virtual void UpdateActual(bool? isUChecked, bool? isDChecked, bool? isWChecked, bool? isWOWChecked)
        {
            double? lastValue = yValuePriv;

            double d = Convert.ToDouble(Actual);
            if (!Convert.ToBoolean(isUChecked))
                d -= Convert.ToDouble(U);
            if (!Convert.ToBoolean(isDChecked))
                d -= Convert.ToDouble(D);
            if (!Convert.ToBoolean(isWChecked))
                d -= Convert.ToDouble(W);
            if (!Convert.ToBoolean(isWOWChecked))
                d -= Convert.ToDouble(WOW);
            if (Length != null && Length != 0 && SumType != null && SumType.ToUpper().Equals("AVARAGE"))
                d = Convert.ToDouble(Length) / (d * 60);
            yValuePriv = d;
            if (yValuePriv != lastValue)
                NotifyPropertyChanged("YValue");
        }

Now at the older versions of Telerik, my chart got updated nicely when this method was executed. However with latest version, this does not happen. I also have a datagrid (telerik) which does reflects the changes done in UpdateActual method. Do i have to rewrite the program, so the chart rebind to the observablecollection every time a change occur, or is there any other way to do this?

[Evgenia]

Hello kjellerik,

Version 2010.2.924 of RadChart doesn't provide item property changed notification so you should Rebind the Chart in order to have it updated.

Please let me know if other questions arise.

Regards,
Evgenia
the Telerik team