syncfusion chart does not display data - mvvm

Question

I added SFchart, it had no errors and it compiles. It shows an empty chartview.
I'm using MVVMcross in Xamarin.IOS
The data I requested is there, it contains about 200 rows, the data is requested from my api with the method override void viewAppearing.
My view in viewdidload:
//Initialize the Chart with required frame. This frame can be any rectangle, which bounds inside the view.
SFChart chart = new SFChart();
chart.Frame = this.headerView.Frame;
//Adding Primary Axis for the Chart.
SFCategoryAxis primaryAxis = new SFCategoryAxis();
chart.PrimaryAxis = primaryAxis;
//Adding Secondary Axis for the Chart.
SFNumericalAxis secondaryAxis = new SFNumericalAxis();
chart.SecondaryAxis = secondaryAxis;
chart.Series.Add(new SFColumnSeries()
{
ItemsSource = (this.ViewModel as UserCoinViewModel).CoinHistory,
XBindingPath = "price_btc",
YBindingPath = "timestamp"
});
this.View.AddSubview(chart);
viewmodel:
private List<CoinHistoryModel> _CoinHistory;
public List<CoinHistoryModel> CoinHistory
{
get
{
return _CoinHistory;
}
set
{
_CoinHistory = value;
RaisePropertyChanged(() => CoinHistory);
}
}

Answer 1

Because you are using MVVMcross, you should use bind method to set your Series's ItemsSource. You just set the ItemsSource to the viewModel instance's property, when the value changed it will not notify the View. So it seems to show an empty chart.
Modify your code to bind like:
SFColumnSeries series = new SFColumnSeries()
{
XBindingPath = "price_btc",
YBindingPath = "timestamp"
};
chart.Series.Add(series);
var set = this.CreateBindingSet<YourView, UserCoinViewModel>();
...
set.Bind(series).For(s => s.ItemsSource).To(vm => vm.CoinHistory);
...
set.Apply();
Then in your ViewModel, create a command like:
private MvxCommand loadDataCommand;
public ICommand LoadDataCommand
{
get
{
return loadDataCommand ?? (loadDataCommand = new MvxCommand(ExecuteloadDataCommand));
}
}
private void ExecuteloadDataCommand()
{
CoinHistory = new List<CoinHistoryModel>()
{
new CoinHistoryModel{ price_btc = "First", timestamp = 10 },
new CoinHistoryModel{ price_btc = "Second", timestamp = 20 },
new CoinHistoryModel{ price_btc = "Third", timestamp = 30 }
};
// Change it to your data request here
}
At last trigger this command in your ViewWillAppear() event:
public override void ViewWillAppear(bool animated)
{
base.ViewWillAppear(animated);
(ViewModel as UserCoinViewModel).LoadDataCommand.Execute(null);
// You can also bind a button to this command to trigger it manually.
}