How can I add values from a datagridview into a pie chart in vb.net?

Question

I would like to represent 2 values from a datagridview into a pie chart. These values are integers and have already been displayed in the datagridview. I just need those values to be displayed in a pie chart. Here is what I've tried:

    For Count As Integer = 0 To DataGridView1.Rows.Count - 2
        Chart1.Series(0).Points.Add(DataGridView1.Item(0, Count).Value, DataGridView1.Item(1, Count).Value)
        Chart1.Series(1).Points.Add(DataGridView1.Item(0, Count).Value, DataGridView1.Item(1, Count).Value)
    Next

This creates a loop to insert all values from the datagridview into the chart. The problem is that when it runs, the chart does not display these two integers.

Answer 1

1. Declare the x and y values and the series of the pie chart.

   Dim series As String = "Time"
   Dim yval As Double() = { x, y }
   Dim xval As String() = {"Time Studying", "Time Not Studying"}
   

2. Retrieve the values from the data grid view.

   For Count As Integer = 0 To DataGridView1.Rows.Count - 2
       x = DataGridView1.Item(0, Count).Value
       y = DataGridView1.Item(1, Count).Value
   Next
   

3. Clear the graph values

    Chart1.Series.Clear()
    Chart1.Titles.Clear()
   

4. Plot values into chart.

   Chart1.Series.Add(series)
   Chart1.Series(series).Points.DataBindXY(xval, yval)
   Chart1.Series("Time").IsValueShownAsLabel = True
   Chart1.Series(series).Points(0).Color = Color.LightSkyBlue
   Chart1.Series(series).Points(1).Color = Color.Orange
   Chart1.Series(series).ChartType = SeriesChartType.Pie