Drawing line on a click on ZedGraph Pane

问题

I have a bit different kind of requirement for ZedGraph.

I want to create the curves on the ZedGraph pane when user clicks on the ZedGraph pane. Also, I have other graphs plotted on that pane. But i want that whenever user clicks on the zedGraph area, we get the co-ordinates where user have clicked and i draw a straigth line on that clicked co-ordinate.

I have used the MouseCLick event alogn with the FindNearestObject method like the following way:

private void zedGraph_RenderedTrack_MouseClick(object sender, EventArgs e)
    {
        MouseEventArgs xx = (MouseEventArgs)e;
        object nearestObject;
        int index;
        this.zedGraph_RenderedTrack.GraphPane.FindNearestObject(new PointF(xx.X, xx.Y), this.CreateGraphics(), out nearestObject, out index);
        if (nearestObject != null)
        {
            DrawALine(xx.X, Color.Red, true);
        }
    }

But using this, ZedGraph search for some curve and find the nearest points and then plot the line but i want that the line be drawn where ever the user clicks. Is there any method to do so?

回答1:

You could try the following code, which will draw a vertical line for a mouse click event.

public Form1()
    {
        InitializeComponent();
    }        

    PointPairList userClickrList = new PointPairList();
    LineItem userClickCurve = new LineItem("userClickCurve");

    private void zedGraphControl1_MouseClick(object sender, MouseEventArgs e)
    {
        // Create an instance of Graph Pane
        GraphPane myPane = zedGraphControl1.GraphPane;

        // x & y variables to store the axis values
        double xVal;
        double yVal;

        // Clear the previous values if any
        userClickrList.Clear();

        myPane.Legend.IsVisible = false;

        // Use the current mouse locations to get the corresponding 
        // X & Y CO-Ordinates
        myPane.ReverseTransform(e.Location, out xVal, out yVal);

        // Create a list using the above x & y values
        userClickrList.Add(xVal, myPane.YAxis.Scale.Max);
        userClickrList.Add(xVal, myPane.YAxis.Scale.Min);

        // Add a curve
        userClickCurve = myPane.AddCurve(" ", userClickrList, Color.Red, SymbolType.None);

        zedGraphControl1.Refresh();
    }

you just have to change the userClickList to draw horizontal line.

Happy Coding.....:)

来源：https://stackoverflow.com/questions/12422398/drawing-line-on-a-click-on-zedgraph-pane

标签

zedgraph