An item with the same key has already been added.

[Ian Leatherbury]

Trying to add 2 different Series to my line chart and getting the error: A System.ArgumentException was thrown: An item with the same key has already been added.

Here's my XAML:

<?xml version="1.0" encoding="UTF-8"?>
<ContentPage 
    xmlns="http://xamarin.com/schemas/2014/forms" 
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" 
    x:Class="tryfsharpforms.ChartPage"
    xmlns:chart="clr-namespace:Syncfusion.SfChart.XForms;assembly=Syncfusion.SfChart.XForms" >
    <ContentPage.Content>
        <chart:SfChart x:Name="CompareChart">

<!--        Primary Axis-->
            <chart:SfChart.PrimaryAxis>
              <chart:CategoryAxis LabelRotationAngle = "-45">
                <chart:CategoryAxis.Title>
                  <chart:ChartAxisTitle Text ="Date"/>
                </chart:CategoryAxis.Title>
              </chart:CategoryAxis>
            </chart:SfChart.PrimaryAxis>

<!--        Secondary Axis-->
            <chart:SfChart.SecondaryAxis>
              <chart:NumericalAxis>
                <chart:NumericalAxis.Title>
                  <chart:ChartAxisTitle Text ="Price"/>
                </chart:NumericalAxis.Title>
              </chart:NumericalAxis>
            </chart:SfChart.SecondaryAxis>
        
<!--            Line Graph-->
      <chart:SfChart.Series>
        <chart:LineSeries StrokeWidth="3" ItemsSource="{Binding StockData1}" XBindingPath="Date" YBindingPath="Close" x:Name="Series1">
          <chart:LineSeries.DataMarker>
            <chart:ChartDataMarker>
              <chart:ChartDataMarker.LabelStyle>
                <chart:DataMarkerLabelStyle Angle ="315"/>
              </chart:ChartDataMarker.LabelStyle>
            </chart:ChartDataMarker>
          </chart:LineSeries.DataMarker>
        </chart:LineSeries>
      </chart:SfChart.Series>

      <chart:SfChart.Series>
        <chart:LineSeries StrokeWidth="3" ItemsSource="{Binding StockData2}" XBindingPath="Date" YBindingPath="Close" x:Name="Series2">
          <chart:LineSeries.DataMarker>
            <chart:ChartDataMarker>
              <chart:ChartDataMarker.LabelStyle>
                <chart:DataMarkerLabelStyle Angle ="315"/>
              </chart:ChartDataMarker.LabelStyle>
            </chart:ChartDataMarker>
          </chart:LineSeries.DataMarker>
        </chart:LineSeries>
      </chart:SfChart.Series>

<!--      End Line Graph-->
    </chart:SfChart>
    </ContentPage.Content>
</ContentPage>

[Ian Leatherbury]

Figured it out. They key was to enclose both Series within <chart:SfChart.Series>. e.g.

 <chart:SfChart.Series>

        <chart:LineSeries StrokeWidth="3" ItemsSource="{Binding StockData1}" XBindingPath="Date" YBindingPath="Close" x:Name="Series1">

        <chart:LineSeries StrokeWidth="3" ItemsSource="{Binding StockData2}" XBindingPath="Date" YBindingPath="Close" x:Name="Series1">  

 </chart:SfChart.Series>

[Suresh B]

Hi lan,

Thanks for using Syncfusion product.

We are glad to know that your issue is resolved. Please get back to us if you need any further assistance.

Thanks for your update.

Regards,
Suresh B