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c#winformscharts

Problem with drawing a chart in Visual Studio

Note: I am using .NET 6 that does not have a chart in Windows Form. I am using winforms-datavisualization.

I have a project that analyzes a text file on the frequency of each letter and creates Histogram with it. Problems occur when I try to draw the graph with a sorted dictionary.

Using

chart1.Series.Add(series);

var keys = sortedFrequencies.Keys.ToList();
var values = sortedFrequencies.Values.ToList();

for (int i = 0; i < keys.Count; i++) {
    int pointIndex = series.Points.AddXY(keys[i], values[i]);
    series.Points[pointIndex].AxisLabel = keys[i].ToString();
    textBox1.Text += keys[i].ToString();
    textBox2.Text += values[i].ToString();
}

chart1.ChartAreas[0].AxisX.Interval = 1;
chart1.ChartAreas[0].AxisX.LabelStyle.Angle = -45;
chart1.ChartAreas[0].AxisX.LabelStyle.IsStaggered = true;
chart1.Invalidate();

I get all columns, but they are not sorted for some reason: enter image description here

And when i change var keys = sortedFrequencies.Keys.ToList(); to var keys = sortedFrequencies.Keys.Select(k => k.ToString()).ToList();

I get what seems like a sorted graph, but all the columns overlap: enter image description here

Full code:

    private Dictionary<char, int> charFrequencies;

    public Form1() {
        InitializeComponent();
        charFrequencies = new Dictionary<char, int>();
    }

    private void chart1_Click(object sender, EventArgs e) { }

    private void buttonLoadFile_Click_1(object sender, EventArgs e) {
        OpenFileDialog fileDialog = new OpenFileDialog();
        if (fileDialog.ShowDialog() == DialogResult.OK) {
            textBoxFilePath.Text = fileDialog.FileName;
            AnalyzeFile(fileDialog.FileName);
            DrawHistogram(charFrequencies); // Показати початкові дані
        }
    }

    private void AnalyzeFile(string filePath) {
        charFrequencies.Clear();
        string text = File.ReadAllText(filePath).ToLower();
        foreach (char c in text) {
            if (char.IsLetter(c)) {
                if (charFrequencies.ContainsKey(c)) {
                    charFrequencies[c]++;
                } else {
                    charFrequencies[c] = 1;
                }
            }
        }
    }

    private void DrawHistogram(Dictionary<char, int> sortedFrequencies) {
        chart1.Series.Clear();
        Series series = new Series {
            Name = "Frequency",
            IsVisibleInLegend = false,
            ChartType = SeriesChartType.Column
        };

        textBox1.Clear();
        textBox2.Clear();

        chart1.Series.Add(series);

        var keys = sortedFrequencies.Keys.ToList();
        var values = sortedFrequencies.Values.ToList();

        for (int i = 0; i < keys.Count; i++) {
            int pointIndex = series.Points.AddXY(keys[i], values[i]);
            series.Points[pointIndex].AxisLabel = keys[i].ToString();
            textBox1.Text += keys[i].ToString();
            textBox2.Text += values[i].ToString();
        }

        chart1.ChartAreas[0].AxisX.Interval = 1;
        chart1.ChartAreas[0].AxisX.LabelStyle.Angle = -45;
        chart1.ChartAreas[0].AxisX.LabelStyle.IsStaggered = true;
        chart1.Invalidate();
    }

    private Dictionary<char, int> SortAlphabetically() {
        return charFrequencies.OrderBy(pair => pair.Key).ToDictionary(pair => pair.Key, pair => pair.Value);
    }

    private Dictionary<char, int> SortByFrequencyDesc() {
        return charFrequencies.OrderByDescending(pair => pair.Value).ToDictionary(pair => pair.Key, pair => pair.Value);
    }

    private Dictionary<char, int> SortByFrequencyAsc() {
        return charFrequencies.OrderBy(pair => pair.Value).ToDictionary(pair => pair.Key, pair => pair.Value);
    }

    private void Form1_Load(object sender, EventArgs e) { }

    private void button1_Click(object sender, EventArgs e) {
        DrawHistogram(SortAlphabetically());
    }

    private void button2_Click(object sender, EventArgs e) {
        DrawHistogram(SortByFrequencyDesc());
    }

    private void button3_Click(object sender, EventArgs e) {
        DrawHistogram(SortByFrequencyAsc());
    }

    private void textBoxFilePath_TextChanged(object sender, EventArgs e) { }
}
Solution

  • I reproduced your issue locally and resolved it by using the following code:

    for (int i = 0; i < keys.Count; i++)
{
  int pointIndex = series.Points.AddXY(i, values[i]); //Note "AddXY(i, "
  series.Points[pointIndex].AxisLabel = keys[i].ToString();
}