鼠标左键单击时如何在 TeeChart 中获取 Y 轴值

Question

当鼠标左键单击图表时，我正在尝试获取多个系列的 y 轴值。

private void mainTChart_MouseDown(object sender, MouseEventArgs e)
{
     if (e.Button == MouseButtons.Left)
     {
          mainTChart.Axes.Bottom.CalcMinMax(ref minTime, ref maxTime);
          cdens = mainTChart.Series[0].YValues.Value[e.Y];
          cvisc = mainTChart.Series[1].YValues.Value[e.Y];
          //cvisc = mainTChart.Series[1].YScreenToValue(e.Y);
     }
}

上面代码的问题是我有时会出现索引异常。 我将鼠标 Y 坐标作为values[list] 的索引。 有时我的鼠标 y 坐标索引高于 values[list] 的范围。

谁能建议我如何获取鼠标点击点的索引。还是将鼠标坐标转换为索引？

如何获取所有系列的 y 轴值？

Answer 1

上面代码的问题是我摆脱了索引异常 有时。

您应该检查索引是否不同于 -1，这意味着没有点被点击。

谁能建议我如何获取鼠标点击点的索引。或者 将鼠标坐标转换为索引？

您应该使用系列的Clicked 方法。 TeeChart for .NET forum、for example 上提供了大量示例：

public Form1()
{
  InitializeComponent();
  InitializeChart();
}

private Steema.TeeChart.Styles.FastLine fastLine1;

private void InitializeChart()
{
  tChart1.Aspect.View3D = false;
  tChart1.MouseMove += new MouseEventHandler(tChart1_MouseMove);

  fastLine1 = new Steema.TeeChart.Styles.FastLine(tChart1.Chart);
  fastLine1.FillSampleValues();
  fastLine1.MouseEnter += new EventHandler(fastLine1_MouseEnter);
}

private int x, y;

void tChart1_MouseMove(object sender, MouseEventArgs e)
{
  x = e.X;
  y = e.Y;
}

void fastLine1_MouseEnter(object sender, EventArgs e)
{
  int index = fastLine1.Clicked(x, y);

  if (index != -1)
  {
    tChart1.Header.Text = index.ToString();
  }
}

如何获取所有系列的y轴值？

在 TeeChart 功能演示中有一个示例。例如What's New?\Welcome !\New in Series\Interpolating line series。该演示可以在 TeeChart 的程序组中找到。下面是示例代码：

public class Line_Interpolate : Steema.TeeChart.Samples.BaseForm
{
    private Steema.TeeChart.Styles.Line line1;
    private Steema.TeeChart.Styles.Line line2;
    private Steema.TeeChart.Styles.Line line3;
    private Steema.TeeChart.Tools.CursorTool cursorTool1;
    private System.Windows.Forms.CheckBox checkBox1;
    private System.ComponentModel.IContainer components = null;
    private Steema.TeeChart.Tools.GridBand gridBand1;
    private double xval;

    /// <summary>
    /// Calculate y=y(x) for arbitrary x. Works fine only for line series with ordered x values.
    /// </summary>
    /// <param name="series"></param>
    /// <param name="firstindex"></param>
    /// <param name="lastindex"></param>
    /// <param name="xvalue"></param>
    /// <returns>y=y(xvalue) where xvalue is arbitrary x value.</returns>
    private double InterpolateLineSeries(TeeChart.Styles.Custom series, int firstindex, int lastindex, double xvalue)
    {
      int index;
      for (index=firstindex; index<=lastindex; index++)
      {
        if (index == -1 || series.XValues.Value[index]>xvalue) break;
      }
      // safeguard
      if (index<1) index = 1;
      else if (index>=series.Count) index = series.Count -1;
      // y=(y2-y1)/(x2-x1)*(x-x1)+y1
      double dx = series.XValues[index] - series.XValues[index-1];
      double dy = series.YValues[index] - series.YValues[index-1];
      if (dx!=0.0) return dy*(xvalue - series.XValues[index-1])/dx + series.YValues[index-1];
      else return 0.0;
    }

    private double InterpolateLineSeries(TeeChart.Styles.Custom series,double xvalue)
    {
      return InterpolateLineSeries(series,series.FirstVisibleIndex,series.LastVisibleIndex,xvalue);
    }

    public Line_Interpolate()
    {
        // This call is required by the Windows Form Designer.
        InitializeComponent();

        foreach (TeeChart.Styles.Series s in tChart1.Series)
    s.FillSampleValues(20);
    }

    /// <summary>
    /// Clean up any resources being used.
    /// </summary>
    protected override void Dispose( bool disposing )
    {
        if( disposing )
        {
            if (components != null) 
            {
                components.Dispose();
            }
        }
        base.Dispose( disposing );
    }

    private void cursorTool1_Change(object sender, Steema.TeeChart.Tools.CursorChangeEventArgs e)
    {
      xval = e.XValue;
      tChart1.Header.Text = "";
      for (int i=0; i<tChart1.Series.Count; i++)
        if (tChart1.Series[i] is TeeChart.Styles.Custom)
        {
          tChart1.Header.Text += tChart1.Series[i].Title + ": Y("+e.XValue.ToString("0.00")+")= ";
          tChart1.Header.Text += InterpolateLineSeries(tChart1.Series[i] as Steema.TeeChart.Styles.Custom,e.XValue).ToString("0.00")+"\r\n";
        }
    }

    private void Line_Interpolate_Load(object sender, System.EventArgs e)
    {
      cursorTool1_Change(tChart1,new Steema.TeeChart.Tools.CursorChangeEventArgs());
    }

    private void tChart1_AfterDraw(object sender, Steema.TeeChart.Drawing.Graphics3D g)
    {
      if (checkBox1.Checked)
      {
        int xs = tChart1.Axes.Bottom.CalcXPosValue(xval);
        int ys;
        g.Brush.Visible = true;
        g.Brush.Solid = true;
        for (int i=0; i<tChart1.Series.Count; i++)
          if (tChart1.Series[i] is TeeChart.Styles.Custom)
          {
            ys = tChart1.Series[i].GetVertAxis.CalcYPosValue(InterpolateLineSeries(tChart1.Series[i] as Steema.TeeChart.Styles.Custom,xval));
            g.Brush.Color = tChart1.Series[i].Color;
            g.Ellipse(new Rectangle(xs-4,ys-4,8,8));
          }
      }
    }
}