C# Chart数据绑定问题，求助

调用绑定数据函数，第一句话就出错，说超出索引！！！求解...
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//绑定数据函数
public static void DrawSpline(double []listX , double [] listY, Chart chart1)
{
try
{
//X.Y值成员
chart1.Series[0].Points.DataBindXY(listX, listY);//<--------这句话就出错！！！
//chart1.Series[0].Points.DataBindY(listY);

//点颜色
chart1.Series[0].MarkerColor = Color.Green;
chart1.Series[0].ChartType = SeriesChartType.Spline;
catch
...
}
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//调用语句
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{
double [] xData = {1,2,3,4,5,6,7,8 };
double[] yData = { 0.2f, 0.3f, 0.1f, 0.4f, 0.1f,0.4f,0.8f,0.5f };
DrawClass.DrawSpline(xData, yData, chart1);
}