Change color of bars depending on value in Highchart bar-chart with MVC3

Question

I am using Dotnet Highchart with MVC3

I am currently working with a diagram that looks like this:

I am trying to modify my code so I can change color on the bars depending on what number they have. I also wonder how I can remove the button "Snittbetyg" as you see can on the image.

This is my code:

 public ActionResult OfficeStatistic()
        {
            {

                Highcharts chart1 = new Highcharts("chart1")
                    .SetXAxis(new XAxis { Categories = new[] { "Ödmjukhet", "Engagemang", "Kompetens", "Lönsamhet" } })
                    .SetYAxis(new YAxis { Title = new YAxisTitle { Text = "Betygskalan" } })
                    .SetSeries(new Series { Data = new Data(new object[] { 1, 8, 9, 6 }), Name = "Snittbetyg" })
                    .SetTitle(new Title { Text = "Örebro Statistik" })
                    .InitChart(new Chart { DefaultSeriesType = ChartTypes.Column });

                return View(chart1);

            }

        }

Any kind of help is appreciated.

Thanks in advance!

Answer 1

I haven't used Highchart but you can download examples from their codeplex page. It looks like both of your requirements can be achieved easily.

Remove the "Snittbetyg" button

Disable the legend:

.SetLegend(new Legend { Enabled = false });

Add Colours

For the series data use points instead of just the numbers:

Data data = new Data(new[]
{
    new Point { Y = 1, Color = System.Drawing.Color.Red },
    new Point { Y = 8, Color = System.Drawing.Color.Blue },
    new Point { Y = 9, Color = System.Drawing.Color.Green },
    new Point { Y = 6, Color = System.Drawing.Color.Black }
});

Highcharts chart1 = new Highcharts("chart1")
    .SetXAxis(new XAxis { Categories = new[] { "Ödmjukhet", "Engagemang", "Kompetens", "Lönsamhet" } })
    .SetYAxis(new YAxis { Title = new YAxisTitle { Text = "Betygskalan" } })
    .SetSeries(new Series { Data = data, Name = "Snittbetyg" })
    .SetTitle(new Title { Text = "Örebro Statistik" })
    .InitChart(new Chart { DefaultSeriesType = ChartTypes.Column })
    .SetLegend(new Legend { Enabled = false });

---

There doesn't seem to be a built in way to make highchart automatically colour the bar based on the y-value. I believe you would have to pick the colour yourself, e.g:

    private System.Drawing.Color GetBarColour(int value)
    {
        if (value < 5) return System.Drawing.Color.Red;
        if (value > 7) return System.Drawing.Color.Green;
        return System.Drawing.Color.Orange;
    }

    public ActionResult OfficeStatistic()
    {
        {
            var dataItems = new[] {1, 8, 9, 6};
            Data data = new Data(
                dataItems.Select(y => new Point {Color = GetBarColour(y), Y = y}).ToArray()
            );

            Highcharts chart1 = new Highcharts("chart1")
                .SetXAxis(new XAxis { Categories = new[] { "Ödmjukhet", "Engagemang", "Kompetens", "Lönsamhet" } })
                .SetYAxis(new YAxis { Title = new YAxisTitle { Text = "Betygskalan" } })
                .SetSeries(new Series { Data = data, Name = "Snittbetyg" })
                .SetTitle(new Title { Text = "Örebro Statistik" })
                .InitChart(new Chart { DefaultSeriesType = ChartTypes.Column })
                .SetLegend(new Legend { Enabled = false });

Answer 2

1. First, define a Tuple list first item is for color and second item point value

   List<Tuple<string, Object>> dataItems = new List<Tuple<string, Object>>();
   

2. i am passing value with swtich it is not neccessary

   SqlDataReader reader = myComm.ExecuteReader();

       if (reader.HasRows)
       {               
           string colorName ="";
           while (reader.Read())                   
           {
               switch ((string)reader.GetValue(1))
               {
                   case "Total Employee(s)":
                       colorName = "Blue";
                       break;
                   case "Present":                       
                       colorName = "Green";
                       break;
                   case "Late":
                   case"Absent":
                   case "During Less":
                   case "Early Going":
                       colorName = "Red";
                       break;
                   case "Leave":
                       colorName = "Orange";
                       break;
                   default:
                       colorName = "Gray";
                       break;
               }
   
               dataItems.Add(new Tuple<string, Object>(colorName, reader.GetValue(2)));
   }
   

3. Now, Finally add Data into series object

   new Series{
    Name = "Employees",
    Data  = new Data(
       dataItems.Select(y => new Point { 
        Color = System.Drawing.Color.FromName(y.Item1), 
        Y = (int)y.Item2 }).ToArray()
       )               
    }