[RESOLVED] Help with point graph

Hi

I am trying to create a coordinates graph using point chart, pulling the data from the MS sql server. 

I want help with the following:

1. How can I change the colour of the point on the chart for my latest data entry?

2. How title my axis as N, S, E & W?  I can only get as shown in figure.

Chart1.ChartAreas(0).AxisX.Title = "W"
Chart1.ChartAreas(0).AxisY.Title = "S"

3. Also, can I the coordinates value just buy hovering over the points on the graph?

Or is there a better way of creating a coordinate graph?

Thanks a lot in advance

Harkirat

sorry i dont know how to attach an image in the forum. :(

Hi harkirat,

Please try to refer to the following solution:

1. Please try to according to your data, and using Chart1.Series["Series1"].Points[pointIndex].Color = System.Drawing.Color.Red; to update color;
   
2. I think the chart only supports two dimensions;
3. Please try to using ToolTip to achieve the mouse hovering.

The following code is my sample, please try to refer it:

In the aspx file:

In the aspx.cs file:

private void FillData()
        {
            double plotY = 50.0;
            if (Chart1.Series["Series1"].Points.Count > 0)
            {
                plotY = Chart1.Series["Series1"].Points[Chart1.Series["Series1"].Points.Count - 1].YValues[0];
                
            }

            Random random = new Random();
            for (int pointIndex = 0; pointIndex < 20; pointIndex++)
            {
                plotY = plotY + (float)(random.NextDouble() * 10.0 - 5.0);
                Chart1.Series["Series1"].Points.AddY(plotY);
                Chart1.Series["Series1"].Points[pointIndex].ToolTip = plotY.ToString();
                if (plotY > 40)// you can also according to data to change the color.
                {
                    Chart1.Series["Series1"].Points[pointIndex].Color = System.Drawing.Color.Red;
                    

                }
            }
        }

Hope it can help you.

If your problem still exists, please let me know.

Best Regards,

Terry Guo

Hi Terry

Thanks a million for your reply. Problems:

1. Sorted, thank you

2.Sad to hear about that, is there other type of chart I can use to get all 4 coordinate axis(x, -x,  y, -y)??

3. I cannot get the code to work. I am struggling a lot with it because I cannot interpret whats going on in there, small comments will be handy, thanks. ;)

This is how I am using with my existing code, can you please correct me.

Imports System.Web.UI.DataVisualization.Charting
Imports System.Data.OleDb
Imports System.Data.SqlClient

Public Class db_con
    Inherits System.Web.UI.Page

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        FillData()
        Dim mySelectQuery As String = "SELECT TOP 5 test_x, test_y FROM test_x_y ORDER BY test_id DESC;"

        Dim myConnection As New SqlConnection("Data Source= ONC-ECC54; Initial Catalog=graph_test; Integrated Security=True")
        Try
            ' Open the connection
            myConnection.Open()

            ' Create a database command on the connection using query
            Dim myCommand As New SqlCommand(mySelectQuery, myConnection)

            ' Create a database reader
            Dim myReader As SqlDataReader = myCommand.ExecuteReader(CommandBehavior.CloseConnection)
   
            Chart1.Series("Series1").Points.DataBindXY(myReader, "test_x", myReader, "test_y")

            ' Close the reader and the connection
            myReader.Close()
            myConnection.Close()

        Catch Ex As Exception
            Label1.Text = "Error in acquiring graph chart " & Ex.ToString
        End Try


        Chart1.Series(0).Color = Drawing.Color.RosyBrown
        Chart1.Series(0).Points(0).Color = System.Drawing.Color.Red

        Chart1.ChartAreas(0).AxisX.Minimum = -10
        Chart1.ChartAreas(0).AxisX.Maximum = 10
        
        Chart1.ChartAreas(0).AxisY.Minimum = -10
        Chart1.ChartAreas(0).AxisY.Maximum = 10


    End Sub

    Private Sub FillData()
        Dim plotY As Double = 50.0
        If (Chart1.Series(0).Points.Count > 0) Then
            plotY = Chart1.Series(0).Points(Chart1.Series(0).Points.Count - 1).YValues(0)
        End If

        Dim rnd1 As New Random()
        For pointIndex As Integer = 0 To 20 Step 1
            plotY = plotY + (rnd1.NextDouble() * 10.0 - 5.0)
            Chart1.Series(0).Points.AddY(plotY)
            Chart1.Series(0).Points(pointIndex).ToolTip = plotY.ToString
            If plotY > 40 Then
                Chart1.Series(0).Points(pointIndex).Color = Drawing.Color.AliceBlue
            End If
        Next
        Debug.WriteLine("")
    End Sub
End Class

in my aspx file:

Thanks alot in advance

Harkirat