Windows forms C# how to make the grid lines of a chart square?

Question

I have a chart in windows forms and I want the gridlines to be squared. The gridline is anchored to bottom, top, left and right so it resizes with the screen. How do I make the grid lines always square and make the whole chart resize with the screen?

I have tried setting the width and height to be the same, but it doesn't work since the series names of the chart are on the right.

EDIT 1: Here is the full uncensored code:

chart1.ChartAreas[0].AxisY.Minimum = 0;
chart1.ChartAreas[0].AxisY.Maximum = max;
chart1.ChartAreas[0].AxisX.Minimum = 0;
chart1.ChartAreas[0].AxisX.Maximum = max;
chart1.ChartAreas[0].AxisX.LabelStyle.Format = "0";
chart1.ChartAreas[0].AxisY.LabelStyle.Format = "0";
chart1.ChartAreas[0].AxisX.Interval = 1;
chart1.ChartAreas[0].AxisY.Interval = 1;

chart1.ChartAreas[0].AxisX.IntervalAutoMode = IntervalAutoMode.FixedCount;
chart1.ChartAreas[0].RecalculateAxesScale();
for (int i = 0; i < points.ToArray().Length; i++)
    dt.Rows.Add(pointsArr[i, 0], pointsArr[i, 1]);
chart1.DataSource = dt;

chart1.Series["תחום הפתרונות האפשריים"].BorderWidth = 0;
float[] OptimalPoint = CalculateOptimalPt(convertEq(z), ListArToAr(points));
if (OptimalPoint[0] == 0)
{
    for (int i = 0; i < 2; i++)
    {
        DataPoint dp = new DataPoint();
        dp.SetValueXY(i, OptimalPoint[1]);
        if (i > 0) dp.Color = Color.Transparent;
        chart1.Series["פיתרון אופטימלי"].Points.Add(dp);
    }
}
else
    chart1.Series["פיתרון אופטימלי"].Points.AddXY(OptimalPoint[0], OptimalPoint[1]);
chart1.Series["פיתרון אופטימלי"].Points[0].MarkerSize = 10;
chart1.Series["תחום הפתרונות האפשריים"].XValueMember = "X_Value";
chart1.Series["תחום הפתרונות האפשריים"].YValueMembers = "Y_Value";
chart1.Series["תחום הפתרונות האפשריים"].ChartType = SeriesChartType.Area;
panel1.Visible = false;
panel2.Visible = true;

Answer 1

You can do it by anchoring the chart only to the Top and Left and calculating and setting the Width and Height yourself when Form size changes.

To do so we get fundamental data of the chart in the form constructor.

private readonly Size _innerMargin = new Size(183, 55); // Estimated
private readonly Size _outerMargin;
private readonly float _aspectRatio;

public Form1()
{
    InitializeComponent();

    _outerMargin = Size - chart1.Size;
    Size innerSize = chart1.Size - _innerMargin;

    _aspectRatio = (float)innerSize.Width / innerSize.Height;
}

_innerMargin is the estimated total difference between the chart size and the plot area with the gridlines. I actually got it from a screenshot and measured it in a graphics application.

_outerMargin is the difference of the form size and the chart control size.

This calculation of the initial _aspectRatio assumes the grid lines build perfect squares when the form opens. Instead, you could set this aspect ratio from the known number of squares in X and Y:

_aspectRatio = 16f / 16f; // From your example image.

In the Form_Resize event handler, we then set the new size of the chart. Depending on whether the current aspect ratio (calculated from the theoretical new maximum plot area size) is less than or greater than the original aspect ratio, the height or the width of the chart determines the maximum chart size. The other dimension must be calculated so that the aspect ratio of plot area remains the same.

private void Form1_Resize(object sender, EventArgs e)
{
    Size maxChartSize = Size - _outerMargin;
    Size innerSize = maxChartSize - _innerMargin;

    double currentAspectRatio = (float)innerSize.Width / innerSize.Height;
    if (currentAspectRatio < _aspectRatio) {
        int chartWidth = Width - _outerMargin.Width;
        chart1.Width = chartWidth;
        chart1.Height = (int)((chartWidth - _innerMargin.Width) / _aspectRatio + _innerMargin.Height);
    } else {
        int chartHeight = Height - _outerMargin.Height;
        chart1.Height = chartHeight;
        chart1.Width = (int)((chartHeight - _innerMargin.Height) * _aspectRatio + _innerMargin.Width);
    }
}