Пример кода ниже должен ответить на ваш вопрос.
public virtual void UpdateGraph(double[] xvals, double[] yvals, double minX, double maxX)
{
zedGraphControl1.GraphPane.XAxis.Scale.MaxAuto = false;
zedGraphControl1.GraphPane.XAxis.Scale.MinAuto = false;
zedGraphControl1.GraphPane.XAxis.Scale.Min = minX;
zedGraphControl1.GraphPane.XAxis.Scale.Max = maxX;
zedGraphControl1.GraphPane.YAxis.Scale.Min = 0;
zedGraphControl1.GraphPane.YAxis.Scale.Max = getMax(yvals, xvals, minX, maxX); //get y-value max within the X-value range
updateZedgraphControl(xvals, yvals);
}
protected virtual void updateZedgraphControl(double[] xvals, double[] yvals)
{
zedGraphControl1.GraphPane.CurveList.Clear();
zedGraphControl1.GraphPane.AddCurve(this.curveTitle, xvals, yvals, Color.Black, SymbolType.None);
this.zedGraphControl1.AxisChange();
this.zedGraphControl1.Refresh();
}