CODEWITHSUNDEEP
c#wpfxamlcharts
kleineg
kleineg

Reputation: 491

XAML Chart not populating Line Series despite binding to correct data

I am using the Chart in System.Windows.Controls.DataVisualization.Toolkit and binding to an object of type

ObservableCollection<KeyValuePair<double, double>>

I have my chart set up as in the picture below, and the screenshot has me hovering over the binding source so I know it is binding to the right object. But when I run the program the Chart is completely blank. I know this setup works, I use the exact same code in another program and it works perfectly. The only things I can think of is some missing references or somehow the style of the line not being set.

enter image description here

Edit:

Here is my code, it is a Runge-Kutta differential equation solver. I included the line you gave me near the bottom. 

    public MainWindow()
    {
        InitializeComponent();
    }

    ObservableCollection<KeyValuePair<double, double>> points = new ObservableCollection<KeyValuePair<double, double>>();

    private double function(double t, double y)
    {
        return y + t;
    }

    private void Button_Click(object sender, RoutedEventArgs e)
    {
        points.Clear();
        points.Add(new KeyValuePair<double, double>(0, 1));
        double h = .01;

        for (int i = 0; i < 100; i++)
        {
            double k1 = function(points[i].Key, points[i].Value);
            double k2 = function(points[i].Key + (h / 2.0), points[i].Value + (h / 2.0) * k1);
            double k3 = function(points[i].Key + (h / 2.0), points[i].Value + (h / 2.0) * k2);
            double k4 = function(points[i].Key + h, points[i].Value + h * k3);
            double t = points[i].Key + h;
            double y = points[i].Value + (h / 6.0) * (k1 + 2 * k2 + 2 * k3 + k4);

            points.Add(new KeyValuePair<double, double>(t, y));
        }

        chart.DataContext = points;
    }

Edit (solved):

I refactored into an MVVM project and it works perfectly now. So the moral is, stay away from code behind, even on tiny side projects.

Upvotes: 1

Views: 826

Answers (1)

jsanalytics
jsanalytics

Reputation: 13188

Do this:

In your Window_Loaded event:

  chart.DataContext = points;

In your XAML:

<chartingToolkit:Chart x:Name="chart" Margin="0" Title="Chart Title">
    <chartingToolkit:LineSeries DependentValuePath="Value" IndependentValuePath="Key" ItemsSource="{Binding}" />
</chartingToolkit:Chart>

enter image description here

EDIT: Full code:

    private void Window_Loaded(object sender, RoutedEventArgs e)
    {
        Random r = new Random();
        ObservableCollection<KeyValuePair<double, double>> points = new ObservableCollection<KeyValuePair<double, double>>();

        for (int i = 0; i < 20; i++)
            points.Add(new KeyValuePair<double, double>(i, r.NextDouble()));

        chart1.DataContext = points;
    }
}

This is the chart using your points:

enter image description here

Upvotes: 1

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