RangeSeries LowBinding ValueConverter

[Philipp]

Hi there,

I'm trying to display a range series that is defined by a collection and a gap.

The ObservableCollection is defining the upper limit. The lower limit is defined by the upper limit minus the gap.

For this display I want to use a value converter that returns the lower limit for each upper limit.

<telerik:RadCartesianChart>
    <telerik:RadCartesianChart.HorizontalAxis>
        <telerik:CategoricalAxis />
    </telerik:RadCartesianChart.HorizontalAxis>
    <telerik:RadCartesianChart.VerticalAxis>
        <telerik:LinearAxis/>
    </telerik:RadCartesianChart.VerticalAxis>
    <telerik:RadCartesianChart.Series>
        <telerik:RangeSeries ItemsSource="{Binding Path=SensorParameter.Range_UpperLimit}" HighBinding="Range_UpperLimit" CategoryBinding="RPM">
            <telerik:RangeSeries.LowBinding>
                <MultiBinding Converter="{StaticResource ConvertOKLowValue}">
                    <Binding Path="Range_UpperLimit" />
                    <Binding Path="Range_Gap" />
                </MultiBinding>
            </telerik:RangeSeries.LowBinding>
        </telerik:RangeSeries>
    </telerik:RadCartesianChart.Series>
</telerik:RadCartesianChart>

 

The SensorParameter struct looks like this:

01.public class RPM_Range : ObservableObject
02.{
03.    public float Range_Gap { get; set; }
04.    public ObservableCollection<Range_Limit> Range_UpperLimit { get; set; }
05.}
06.
07.public class Range_Limit: ObservableObject
08.{
09.    public float RPM
10.    {
11.        get; set;
12.    }
13.
14.    public float OK_Range_UpperLimit
15.    {
16.        get; set;
17.    }
18.}

 

The value converter is implemented like this:

01.public class RangeSeriesLowConverter : IMultiValueConverter
02.{
03.    public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
04.    {
05.        double? _RangeUpperLimit = values[0] as double?;
06.        double? _RangeGap = values[1] as double?;
07.        if (_RangeUpperLimit - _RangeGap < 0)
08.            return 0;
09.       return _RangeUpperLimit - _RangeGap;
10.    }
11.
12.    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
13.    {
14.        throw new NotImplementedException();
15.    }
16.}

 

UpperLimit binds correctly. But I'm not getting the binding to the lower limit correctly. While debugging the value converter is called, but the arguments are not passed correctly.

Is there a restriction using value converters for the low binding?

 

Thanks in advance for your help.

Kindly

Philipp

[Martin Ivanov]

Hello Philipp,

The binding properties like LowBinding, HighBinding, ValueBinding, etc., are expecting a DataPointBinding object. When the property is set in XAML it expects a string representing the name of the property that will be used for the corresponding binding. This is the the current code doesn't work.

To acheive your requirement you can use a GenericDataPointBinding for the LowBinding property. You can use the ValueSelector function of the generic binding to get the value that is currently calculated in your converter. The Create Data-Bound Chart article shows how to use the GenericDataPointBinding. 

Regards,
Martin Ivanov
Progress Telerik