Secondary axis on WPF graph

[jsacks]

Hello,

I'm trying to plot a secondary y-axis on my WPF graph. I have a graph bound to an array of AnalogWaveform<double> objects which I change at runtime. This array can be different sizes depending on user selection, however assume that there are two types of data to graph.

I would like to correspond one type of data to my primary y-axis and the other type to my secondary y-axis. For example, I could have four AnalogWaveform<double> objects to plot, two of which are in Hz (primary) and the other two in Volts (secondary).

According to the documentation, I need an extra <axis> element under my <Graph.Axes> definition. What I have is therefore:

         <ni:Graph ...>
            <ni:Graph.Axes>
                <ni:AxisDouble x:Name="_yAxis" Orientation="Vertical" MinorDivisions="{x:Null}">
                    <ni:AxisDouble.LabelTemplate>
                        <DataTemplate>
                            <Label Margin="5" Content="{Binding}"/>
                        </DataTemplate>
                    </ni:AxisDouble.LabelTemplate>
                    <ni:AxisDouble.MajorDivisions>
                        <ni:RangeLabeledDivisions Mode="Count: 11" TickVisibility="Hidden"/>
                    </ni:AxisDouble.MajorDivisions>
                    <ni:AxisDouble.MajorGridLines>
                        <ni:GridLines Stroke="#FFD8D8D8" StrokeThickness="2"/>
                    </ni:AxisDouble.MajorGridLines>
                </ni:AxisDouble>
                <ni:AxisDouble x:Name="_ySecondaryAxis" Orientation="Vertical"  MinorDivisions="{x:Null}">
                    <ni:AxisDouble.MajorDivisions>
                        <ni:RangeLabeledDivisions Mode="Count: 11" TickVisibility="Hidden"/>
                    </ni:AxisDouble.MajorDivisions>
                </ni:AxisDouble>
                <ni:AxisPrecisionDateTime x:Name="_xAxis" Orientation="Horizontal" Label="Time">
                </ni:AxisPrecisionDateTime>
            </ni:Graph.Axes>
            <ni:Graph.Children>
                <ni:MultiPlotCursor Name="_mpCursor" Visibility="Hidden"/>
            </ni:Graph.Children>
        </ni:Graph>

This adds a second y-axis to the left of my primary y-axis. What I need is for this axis to be located to the right of my graph, and somehow to plot each AnalogWaveform<double> on the correct y-axis.

I build my plots in code as follows:

                
                _graph.Plots.Clear();

                // RawData is my AnalogWaveform<double>[], built beforehand based on a server response
                foreach (AnalogWaveform<double> waveform in RawData) 
                {
                    if (waveform != null)
                    {
                        plot = new Plot(waveform.ChannelName);
                        plot.DataContext = waveform;                        
                        
                        plots.Add(plot); //plots is a simple List<plot>
                    }
                }

                _graph.Plots.AddRange(plots); //add plots to graph

                _legend.ItemsSource = plots; //add plots to legend

Any help would be appreciated on how to do this.

Thanks in advance.

[phansen · Accepted solution]

To position your second Y axis on the other side of the graph, set the Location property on the axis to Far.

To associate a plot with a non-default Y axis, set the VerticalScale property on the plot to the appropriate Y axis value.

[jsacks]

Thanks Paul, that works.