NotifyOfPropertyChange does not refresh the data in the map

Question

I have a problem refreshing the data after changing the report selected from combobox. In the ViewModel itself, the data changes, but the view does not refresh. Advice what am I doing wrong? Or what should I improve?

At the start, the data loads well and the map is colored, the only problem is changing the report and thus the lack of map refresh.

This is what I have at xaml:

and this is in ViewModel

public class CountiesMapViewModel : Screen
{
    private CountiesDataProvider _countiesDataProvider = new CountiesDataProvider();
    private MapReportType _mapDataType = new MapReportType();

    private ObservableCollection _report;

    public ObservableCollection Report
    {
        get { return _report; }
        set 
        { 
            _report = value; 
            NotifyOfPropertyChange(() => Report);
        }
    }
    private IEnumerable _counties;
    public IEnumerable Counties
    {
        get { return _counties; }
        set
        {
            _counties = value;
            NotifyOfPropertyChange(() => Counties);
        }
    }

    private ObservableCollection _fromRange;

    public ObservableCollection FromRange
    {
        get { return _fromRange; }
        set
        {
            _fromRange = value;
            NotifyOfPropertyChange(() => FromRange);
        }
    }

    private ObservableCollection _toRange;

    public ObservableCollection ToRange
    {
        get { return _toRange; }
        set
        {
            _toRange = value;
            NotifyOfPropertyChange(() => ToRange);
        }
    }

    public CountiesMapViewModel()
    {
        _counties = _countiesDataProvider.GetCounties;
        Report = new ObservableCollection(PrepareReportData(_counties));
        PrepareDataRanges(Report.Max(rp => rp.DataValue));
    }

    public void PrepareDataRanges(decimal maxValue)
    {
        var fromList = new List();
        var toList = new List();

        var range = Convert.ToInt32(Math.Round(maxValue / 30));
        int lastTo = 0;
        for (int i = 0; i < 30; i++)
        {
            var from = lastTo;
            var to = lastTo + range;
            lastTo = to + 1;
            fromList.Add(from);
            toList.Add(to);
        }
        FromRange = new ObservableCollection(fromList);
        ToRange = new ObservableCollection(toList);
    }
    private ObservableCollection PrepareReportData(IEnumerable counties)
    {
        ObservableCollection prepareReportData = new ObservableCollection();
        switch (SelectedReport)
        {
            case "Liczba Świadczeń":
                foreach (var row in counties)
                {
                    prepareReportData.Add(new MapData()
                    {
                        CountyId = row.CountyId,
                        CountyName = row.County,
                        DataValue = row.NumberOfMedicals,
                        TooltipDataValue = $"Liczba świadczeń: {row.NumberOfMedicals}"
                    });
                }
                break;
            case "Liczba Pacjentów":
                foreach (var row in counties)
                {
                    prepareReportData.Add(new MapData()
                    {
                        CountyId = row.CountyId,
                        CountyName = row.County,
                        DataValue = row.NumberOfPatients,
                        TooltipDataValue = $"Liczba Pacjentów: {row.NumberOfPatients}"
                    });
                }
                break;
            case "Wartość Zrealizowanych Świadczeń":
                foreach (var row in counties)
                {
                    prepareReportData.Add(new MapData()
                    {
                        CountyId = row.CountyId,
                        CountyName = row.County,
                        DataValue = row.Execution,
                        TooltipDataValue = $"Wartość zrealizowanych świadczeń: {row.Execution:C}"
                    });
                }
                break;
            case "Liczba Zrealizowanych Punktów":
                foreach (var row in counties)
                {
                    prepareReportData.Add(new MapData()
                    {
                        CountyId = row.CountyId,
                        CountyName = row.County,
                        DataValue = row.Points,
                        TooltipDataValue = $"Zrealizowane punkty: {row.Points:N2}"
                    });
                }
                break;
        }
        return prepareReportData;
    }
    private List _reportType;

    public List ReportType
    {
        get { return _mapDataType.ReportType; }

        set
        {
            _reportType = value;
            NotifyOfPropertyChange(() => ReportType);
            NotifyOfPropertyChange(() => Report);
        }
    }

    private string _selectedReport = "Liczba Świadczeń";

    public string SelectedReport
    {
        get { return _selectedReport; }
        set
        {
            _selectedReport = value;
            NotifyOfPropertyChange(() => SelectedReport);

            Report = new ObservableCollection(PrepareReportData(_counties));
            PrepareDataRanges(Report.Max(rp => rp.DataValue));
            NotifyOfPropertyChange(() => Report);
        }
    }
}
public class MapData
{
    public int CountyId { get; set; }
    public string CountyName { get; set; }
    public decimal DataValue { get; set; }
    public string TooltipDataValue { get; set; }
}

I'm using CaliburnMicro and syncfusion for Map.

Muhammad Sulaiman · Answer

A couple of things

The combobox is bound to nothing, so when a new value selected for the combobx, the code in the setter of SelectedReport is not executed

This is because you are setting the DataContext for the Map control only, so let's change the way view-viewmodel linkup

Replace

With

Therefore, CountiesMapViewModel will be the DataContext for all of the UserControl.

Now, Remove all the occurrences of DataContext="{StaticResource Vm}" And , Source={StaticResource Vm} in '.xaml', no need for these at all (the second one is not even needed in your old code)

Give it a try..

NotifyOfPropertyChange does not refresh the data in the map

1 Answers