MVVM Binding data

[Grzegorz B]

Dear Syncfusion,

I am affected by new problems using SFLinearGauge and SFChart both related to binding data.

SFLinearGauge

I managed to bind value showed on SFCircularGauge to my ViweModel (still some problems with rendering - mentioned in different topic). Unfortunately the same approach does not work with Linear version of Gauge.

My View (ContentPage) is auto-wired to my ViewModel using Prism. All bindings used in e.g. Labels works without any problems. When I bind in my LinearGauge the value is always 0.

When I set Value manually in XAML it displays correctly. Also coping binding from Gauges Value to Labels Text shows correct value. The variable is of double type. I tried both BarPointer and SymbolPointer.

My XAML:

<gauge:SfLinearGauge HeightRequest="60" Orientation="OrientationHorizontal" BackgroundColor="White">

            <gauge:SfLinearGauge.Scales>

                <gauge:LinearScale MinimumValue="0" MaximumValue="550" Interval="50" LabelColor="Gray" LabelOffset="0.2" ScaleBarSize="10" ScalePosition="Forward" ScaleBarColor="Transparent" FrameOffset="0.1">

                    <gauge:LinearScale.Ranges>

                        ...

                    </gauge:LinearScale.Ranges>

                    <gauge:LinearScale.Pointers>

                        <gauge:SymbolPointer Value="{Binding MyValue}" Color="#0091DC" />

                        <!--<gauge:BarPointer Thickness="15" Value="{Binding MyValue}" Color="#0091DC" />-->

                    </gauge:LinearScale.Pointers>

                </gauge:LinearScale>

            </gauge:SfLinearGauge.Scales>

        </gauge:SfLinearGauge>  

And in ViewModel it is declared like Prism recommends:

private double _myValue;

public double MyValue

{

    get { return _myValue; }

    set { SetProperty(ref _myValue, value); }

}

Is there any difference between Linear and Circular Gauge?

SFChart

I created simple PieChart and populated it with my Custom data (of course all using MVVM approach) (all based on great samples: https://help.syncfusion.com/xamarin/sfchart/overview)

In my constructor of ViewModel I populate data:

PieData = new ObservableCollection<PieChartLabel>();

PieData.Add(new PieChartLabel("Valid", 10));

PieData.Add(new PieChartLabel("Invalid", 20));

PieData.Add(new PieChartLabel("Standstill", 30));

And it shows this data as supposed to. The problem is that the App is going to be a live data app and data showed on Pie chart will change.

Unfortunately changing directly one element:

PieData[index].Value = newData.Value;

Or changing whole collestion:

var pieData = PieData;

pieData[index].Value = newData.Value;

PieData = pieData;

is not working. I can only see first data set in contructor of my VM

I will appreciate all the help.

Best regards,

Grzegorz 

[Pavendhan Kumar]

Hi Grzegorz Bojarczuk,

Thanks for contacting Syncfusion support.

Query regarding SFChart:

You can achieve this requirement using ‘ListenPropertyChange’ property of ChartSeries. We have prepared a sample as per your requirement. Please find the sample from the below location.

Sample : http://www.syncfusion.com/downloads/support/forum/125996/ze/SimpleSample-34646017


Query regarding SFLinearGauge

We were able to reproduce the issue " reported binding issue in LinearGauge” and have logged defect report regarding this. A support incident to track the status of this defect has been created under your account. Please log on to our support website to check for further updates.

https://www.syncfusion.com/account/login?ReturnUrl=%2fsupport%2fdirecttrac%2fincidents/ 

Regards,
Pavendhan K.