从Windows窗体C＃中的列表列表绘制图表

Question

I am trying to draw a stacked graph from my database. I have 10 comboboxes(drop down list). The user can select up to 10 attributes. The values are all double. The values should be normalized and averaged. Normalizing means to move the range of the values between 0 and 1. I get no errors from reading and calculations but when I am trying to draw the chart it gives me index error (out of range). I am not sure what I am doing wrong. Here is my whole code:

SqlCommand cmd = new SqlCommand(command, con);
SqlDataReader reader ;
SqlDataAdapter da = new SqlDataAdapter(cmd);

con.Open();
reader = cmd.ExecuteReader();
DataTable dt = new DataTable();

List<List<double>> list = new List<List<double>>();
List<double> inner;
List<double> Outdistance = new List<double>();
//reading the columns and storing them into list. the coulmns 0 and 2 are not needed. 
while (reader.Read())
{
    inner = new List<double>();
    for(int i = 3;i<reader.FieldCount;i++)
    {
        var temp = reader.GetDouble(i);
        inner.Add(temp);
    }
    list.Add(inner);
    var temp2 = reader.GetDouble(1);
    Outdistance.Add(temp2);
}

con.Close();
List<List<double>> normallist = new List<List<double>>();
List<double> AVGDist = average(Outdistance, 10);

//normalizing the data. data-min/range 
foreach(List<double> l in list)
{
    normallist.Add(normalizer(l));
}
List<List<double>> avgList = new List<List<double>>();

//reducing the amount by averaging every 10 element. 
foreach (List<double> l in normallist)
{
    avgList.Add(average(l,10));
}

//drawing the chart 
foreach (List<double> lst in avgList)
{
    Series S = new Series();
    S.ChartType = SeriesChartType.StackedArea;
    chart1.Series.Add(S);
    for(int i = 0 ; i < lst.Count ; i++)
    {
        this.chart1.Series[S.Name].Points.AddXY(AVGDist[i],lst[i]);
    }
}

public List<double> average(List<double> T , int n)
{
    var currentElement = 0;
    var currentSum = 0.0;
    var newList = new List<double>();

    foreach (var item in T)
    {
        currentSum += item;
        currentElement++;

        if (currentElement == n)
        {
            newList.Add(currentSum / n);
            currentElement = 0;
            currentSum = 0.0;
        }
    }

    if (currentElement > 0)
    {
        newList.Add(currentSum / currentElement);
    }

    return newList;
}

public List<double> normalizer( List<double> T)
{
    double min, max, range;
    min = T.Min();
    max = T.Max();
    range = max - min;

    for (int i = 0; i < T.Count;i++ )
    {
        T[i] = (T[i] - min) / range;
    }
    return T;
}

I also checked my select string but it was correct. I think I am not using the correct code for the charts. Can anyone please help?

Answer 1

The error should be thrown in the below line, this.chart1.Series[S.Name].Points.AddXY(AVGDist[i],lst[i]);

Series has been indexed using S.Name. S.Name should be set to some string, before it can be accessed in the above line.

Answer 2

The code for your charts is correct. And looking at your code, it looks like the index for your AVGDist is going out of bounds in this line

this.chart1.Series[S.Name].Points.AddXY(AVGDist[i],lst[i]);

Add a breakpoint here to debug further.

Answer 3

for(int i=0; i < T.Count -1; i++) << I think the -1 is the problem add it and try.

public List<double> normalizer( List<double> T)
{
    double min, max, range;
    min = T.Min();
    max = T.Max();
    range = max - min;

    for (int i = 0; i < T.Count -1;i++ )
    {
        T[i] = (T[i] - min) / range;
    }
    return T;
}