从c#图表系列中获取y值

我有图表系列:

Series[] tempSeries = new Series[sensorNum];    // Series to hold current/past temperature data for plotting, for each sensor

我给它们添加新的点:

tempSeries[i].Points.AddXY(current_time, temp_F[i]);        // Add new temperature data to series

现在我想把序列转换成字符串，通过套接字发送。

问题是如何从序列中得到Y值?

我试过了:

private string sendAll() {
        string myMsg = "";
        double[,] lastTemp = new double[4, 1200];
        double[,] lastWind = new double[4, 1200];
        for (int i = 0; i < 4; i++) {
            for (int j = 0; j < 1200; j++){
                try
                {
                    lastTemp[i, j] = tempSeries[i].Points[j].YValues[0];
                    myMsg += lastTemp[i, j] + " ";
                }
                catch (Exception ex) {
                    lastTemp[i, j] = 0;
                    myMsg += 0 + " ";
                }
            }
        }
        myMsg += "; ";
        for (int i = 0; i < 4; i++)
        {
            for (int j = 0; j < 1200; j++)
            {
                try
                {
                    lastWind[i, j] = windSeries[i].Points[j].YValues[0];
                    myMsg += lastWind[i, j] + " ";
                }
                catch (Exception ex)
                {
                    lastWind[i, j] = 0;
                    myMsg += 0 + " ";
                }
            }
        }
        MessageBox.Show(myMsg);
        return myMsg;
    }

    StringBuilder sb = new StringBuilder(); 
    for (int i = 0; i < 10000; i++)
    {
        sb.Append("x");
    } 
    string x = sb.ToString();