如何在ZedGraph中引入特定曲线

Question

I have two curves on the zedgraph control, after plotting both the curves...

PointPairList thresholdList = new PointPairList();
PointPairList powerList = new PointPairList();

private void plotPower()
{
        // Create an object to access ZedGraph Pane
        GraphPane pane = zedGraphControl1.GraphPane;            
        LineItem thresholdLine = new LineItem("thresholdLine");
        LineItem powerLine = new LineItem("powerLine");

        // Set the Threshold Limit
        double thresoldLimit = Convert.ToDouble(numAnalysisThreshold2.Value);

        // Points
        double[] x = new double[]{0, pane.XAxis.Scale.Max};
        double[] y = new double[]{thresoldLimit, thresoldLimit};

        // Set the threshold line curve list
        thresholdList.Add(x, y); 

        // Set the Power Line curve list
        powerdList.Add(XData, YData);

        // Add Curves
        thresholdLine = pane.AddCurve("", thresholdList, Color.Red, SymbolType.None);
        powerLine = pane.AddCurve("", powerList, Color.Red, SymbolType.None);

        // Refresh Chart
        this.Invalidate();
        zedGraphControl1.Refresh();
}

from the above code, I managed to plot the two curves as power line curve over the threshold line curve.

Now my questions is, if I want to bring any one of the curve in front....Is there any method available(ex: bringittoFront()....)...?

Thanks a lot for your time ....:)

Answer 1

The GraphPane contains a CurveList property, and the CurveList class is a subclass of List<CurveItem> . If you set the CurveItem.Tag property for each curve that you draw, I believe you should be able to sort the curve items by using the CurveList.Sort(IComparer<CurveItem>) method and using the Tag to represent the sorting order.

UPDATE JUNE 19

Simple example: two lines, the blue line2 with line2.Tag = 2 and the red line1 with line1.Tag = 1 . In the initialization line2 is added first to the graph pane, so it will be displayed on top.

void GraphInit()
{
    var line2 = _graph.GraphPane.AddCurve("Second", 
        new[] { 0.1, 0.5, 0.9 }, new[] { 0.1, 0.5, 0.1 }, Color.Blue);
    line2.Tag = 2;

    var line1 = _graph.GraphPane.AddCurve("First", 
        new[] { 0.1, 0.5, 0.9 }, new[] { 0.1, 0.5, 0.9 }, Color.Red);
    line1.Tag = 1;

    _graph.Refresh();
}

To sort, first implement a class that implements IComparer<CurveItem> , and that sorts the curve items in ascending order based on the numerical value of the CurveItem Tag property:

class CurveItemTagComparer : IComparer<CurveItem>
{
    public int Compare(CurveItem x, CurveItem y)
    {
        return ((int)x.Tag).CompareTo((int)y.Tag);
    }
}

To perform re-sorting and update the graph, implement the following event handler for the Sort button:

void SortButtonClick(object sender, EventArgs e)
{
    _graph.GraphPane.CurveList.Sort(new CurveItemTagComparer());
    _graph.Refresh();
}

Now, when clicking the Sort button, the curves will be sorted such that the curve with the lowest tag value, ie line1 , will instead be drawn on top. Additionally, note that the curve order in the legend is changed along.

Answer 2

There is a very easy way. Use the Move() method in the CurveList class. For example in:

zedGraphControl1.GraphPane.CurveList.Move(index,relativePos)

setting relativePos to -1 will move the object one position earlier in the list, while 1 will move it one position later. To move an item to the beginning of the list, use a large negative value (such as -999 ). To move it to the end of the list, use a large positive value.

Answer 3

And, for who needs it, this is the code for the IComparer class for vb.net:

    Public Class CurveItemTagComparer
    Implements IComparer(Of CurveItem)
    Function Compare(ByVal x As ZedGraph.CurveItem, ByVal y As ZedGraph.CurveItem) As Integer _
    Implements System.Collections.Generic.IComparer(Of CurveItem).Compare
        Return CInt(x.Tag).CompareTo(CInt(y.Tag))
    End Function
End Class

Giovanni