C#从CSV文件中读取字符串并绘制折线图

Question

目前，我可以使用windows窗体应用程序从多个CSV文件中读取数据并绘制折线图。然而，现在我需要根据CSV文件的节名(CSV文件的第三列)绘制一个折线图。

修改/新建CSV文件：(添加节名称列)

Values,Sector,Name
5.55,1024,red
5.37,1536,red
5.73,2048,blue
5.62,2560,.blue
5.12,3072,.yellow
...

1. 基于节名列，我的线形图需要相应地绘制在单线中，不同的节必须用不同的颜色绘制，包括图侧显示的图例必须根据不同的节名显示
2. 1个csv文件=1个系列。但csv文件中有相同的节名(上面显示的csv文件示例，例如前20行为红色)相同的节名称=相同的颜色。如果我打开2个或多个csv文件=2系列。由于csv文件中的节名不同，每个系列将具有不同的颜色

我对编程很陌生，如果有人能帮我编辑代码，我将不胜感激。

谢谢。

Answer 1

更新代码：

GraphDemo(表单)：

List<Read> rrList = new List<Read>();
void openToolStripMenuItem_Click(object sender, EventArgs e)
{
OpenFileDialog ff = new OpenFileDialog();
Read rr;
ff.InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.Desktop); //"C:\";
ff.Filter = "csv files (*.csv)|*.csv|All files (*.*)|*.*";
ff.Multiselect = true;
ff.FilterIndex = 1;
ff.RestoreDirectory = true;
if (ff.ShowDialog() == DialogResult.OK)
{
try
{
rrList.Clear();
foreach (String file in ff.FileNames) //if ((myStream = ff.OpenFile()) != null)
{
rr = new Read(file);
rrList.Add(rr); 
}
//Populate the ComboBoxes
if (rrList.Count > 0)
{
string[] header = rrList[0].header; //header of first file
xBox.DataSource = header; 
yBox.DataSource = header.Clone(); //without Clone the 2 comboboxes link together!
}
if (yBox.Items.Count > 1) yBox.SelectedIndex = 1; //select second item
}
catch (Exception err)
{
//Inform the user if we can't read the file
MessageBox.Show(err.Message);
}
}
}
private void button1_Click(object sender, EventArgs e)
{
Plot.Draw(rrList, xBox, yBox, chart);
}

class阅读：

public class Read
{
public int nLines { get; private set; }
public int nColumns { get; private set; }
public string[] header { get; private set; }
public float[,] data { get; private set; }
public string fileName { get; set; }
public string[] section { get; private set; }
public Read(string file)
{
string[] pieces;
fileName = Path.GetFileName(file);  
string[] lines = File.ReadAllLines(file); // read all lines
if (lines == null || lines.Length < 2) return; //no data in file
header = lines[0].Split(','); //first line is header
nLines = lines.Length - 1; //first line is header
nColumns = header.Length;
//read the numerical data and section name from the file
data = new float[nLines, nColumns - 1]; // *** 1 less than nColumns as last col is sectionName
section = new string[nLines]; // *** 
for (int i = 0; i < nLines; i++) 
{
pieces = lines[i + 1].Split(','); // first line is header
if (pieces.Length != nColumns) { MessageBox.Show("Invalid data at line " + (i + 2) + " of file " + fileName); return; }
for (int j = 0; j < nColumns - 1; j++)
{
float.TryParse(pieces[j], out data[i, j]); //data[i, j] = float.Parse(pieces[j]);
}
section[i] = pieces[nColumns - 1]; //last item is section
}
}
}

class绘图：

public class Plot
{
//public Plot() { } //no constructor required as we use a static class to be called
public static void Draw(List<Read> rrList, ComboBox xBox, ComboBox yBox, Chart chart) //***
{
int indX = xBox.SelectedIndex;
int indY = yBox.SelectedIndex;
chart.Series.Clear(); //ensure that the chart is empty
chart.Legends.Clear();
Legend myLegend = chart.Legends.Add("myLegend");
myLegend.Title = "myTitle";
//define a set of colors to be used for sections
Color[] colors = new Color[] { Color.Black, Color.Blue, Color.Red, Color.Green, Color.Magenta, Color.DarkCyan, Color.Chocolate, Color.DarkMagenta }; 
//use a Dictionary to keep iColor of each section
// key=sectionName, value=iColor (color index in our colors array)
var sectionColors = new Dictionary<string, int>();
int i = 0;
int iColor = -1, maxColor = -1;
foreach (Read rr in rrList)
{
float[,] data = rr.data;
int nLines = rr.nLines;
int nColumns = rr.nColumns;
string[] header = rr.header;
chart.Series.Add("Series" + i);
chart.Series[i].ChartType = SeriesChartType.Line;
//chart.Series[i].LegendText = rr.fileName;
chart.Series[i].IsVisibleInLegend = false; //hide default item from legend
chart.ChartAreas[0].AxisX.LabelStyle.Format = "{F2}";
chart.ChartAreas[0].AxisX.Title = header[indX];
chart.ChartAreas[0].AxisY.Title = header[indY];
for (int j = 0; j < nLines; j++)
{
int k = chart.Series[i].Points.AddXY(data[j, indX], data[j, indY]);
string curSection = rr.section[j];
if (sectionColors.ContainsKey(curSection))
{
iColor = sectionColors[curSection];
}
else
{
maxColor++;
iColor = maxColor; sectionColors[curSection] = iColor;
}
chart.Series[i].Points[k].Color = colors[iColor];
}
i++; //series#
} //end foreach rr
//fill custom legends based on sections/colors
foreach (var x in sectionColors)
{
string section = x.Key;
iColor = x.Value;
myLegend.CustomItems.Add(colors[iColor], section); //new LegendItem()
}
}
}

Answer 2

您可以按节列分隔数据，并使用节名称作为Series集合的索引，而不是使用i。

最好将节名称用作Series.Name。我建议使用一个包含两个数字和字符串的数据类，并将它们收集在List<Dataclass>中。然后为不同的部分创建Series。然后绕过去。。

以下是一些代码示例：

为您的数据定义class：

public class Data3
{
public int N1 { get; set;}
public double N2 { get; set;}
public string S1 { get; set;}
public Data3(double n2, int n1, string s1)
{
N1 = n1; N2 = n2; S1 = s1;
}
}

选择你自己的名字！可选但始终建议：添加一个漂亮的ToString()过载！

声明类级别变量：

List<Data3> data = new List<Data3>();

在读取期间，在那里收集数据：

data.Add(new Data3(Convert.ToDouble(pieces[1]), Convert.ToInt32(pieces[0]), pieces[2]));

要绘制图表，首先创建Series:

var sections= data.Select(x => x.S1).Distinct<string>();
foreach (string s in sections)
chart.Series.Add(new Series(s) { ChartType = SeriesChartType.Line });

然后绘制数据；该系列可以通过其Names:进行索引

foreach (var d in data) chart.Series[d.S1].Points.AddXY(d.N1, d.N2);

我省略了将代码集成到应用程序中的细节；如果你遇到问题，一定要通过编辑你的问题来显示新代码！

几个注意事项：

• 当有疑问时，总是创建一个类来保存您的数据

• 当有疑问时，总是选择类而不是结构

• 当有疑问时，总是选择List<T>而不是阵列

• 总是试着用有用的名称将代码分解成小块。

示例：要读取csv文件中的所有数据，请创建一个函数：

public void AppendCsvToDataList(string file, List<Data3> list)
{
if (File.Exists(file))
{
var lines = File.ReadAllLines(file);
for (int l = 1; l < lines.Length; l++)
{
var pieces = lines[l].Split(',');
list.Add(new Data3(Convert.ToInt32(pieces[1]),
Convert.ToDouble(pieces[0]), pieces[2]));
}
}
}