Line Chart Graphical Alert

Question

I currently have a line graph in my C# program, and I have a min and max variable. If any the graph ever exceeds the max, or goes below the min, is there any built in way of displaying on the graph (such as a dot at the point) that the limit was passed, and display the x/y values for that point?

int max = 2000;
int min = 2000;

for (int i = 0; i < dgvLoadedValues.RowCount - 1; i++)
{
   DateTime x = Convert.ToDateTime(dgvLoadedValues.Rows[i].Cells[0].Value.ToString());

   try
   {
      float y = float.Parse(dgvLoadedValues.Rows[i].Cells[e.ColumnIndex].Value.ToString());
      chart1.Series["Series1"].Points.AddXY(x, y);
   }
   catch
   {
      Console.WriteLine("Unable to plot point");
   }
}

Code above simply shows values taken from a datagridview and displaying it into a line graph

Thank you

Answer 1

Unfortunately there seems to be no way to define such an automatic alert.

But as you know just when the DataPoints are added or bound you can set a Marker where necessary.

Here is a loop that does it after the fact in one go, but of course you can just as well set the markers as you add the points..:

foreach (DataPoint dp in chart1.Series[0].Points)
{
    if (dp.YValues[0] < max && dp.YValues[0] > min ) continue;
    dp.MarkerStyle = MarkerStyle.Circle;
    dp.MarkerColor = Color.Red;
}

Or in your case:

try
{
   float y = float.Parse(dgvLoadedValues.Rows[i].Cells[e.ColumnIndex].Value.ToString());
   int i = chart1.Series["Series1"].Points.AddXY(x, y);
   if (y < min || y > max)
   {
      chart1.Series["Series1"].Points[i].MarkerStyle = MarkerStyle.Circle;
      chart1.Series["Series1"].Points[i].MarkerColor = Color.Red;
   }       
}

To clear a marker you can set its MarkerStyle = MarkerStyle.None.

Of course you could easily give the min and max points different colors..

Here is an example with the simple circle style, but there are others including images..:

To add the values in a label use a format like this:

dp.Label = "(#VALX{0.0} / #VAL{0.0})" ;