Custom label for vb chart - vb.net

Question

#Custom label for vb chart#
I have a datatable like this
XValue
YValue
Title
1
1
A
2
2
B
3
3
C
I want to display a vb chart like this
6|
5|
4|
3| *C
2| *B
1| *A
0|______________________
0 1 2 3 4 5 6 7 5 8 9
so far i can only display this
6|
5|
4|
3| *3
2| *2
1| *1
0|______________________
0 1 2 3 4 5 6 7 5 8 9
this is my code below
Chart20.ChartAreas(0).AxisX.Minimum = 60
Chart20.ChartAreas(0).AxisX.Maximum = 220
Chart20.Series("TEMP").Points.Clear()
Try
CONN.Open()
COMMAND = CONN.CreateCommand
QUERY = "SELECT XValue,YValue,Title FROM vitals"
COMMAND = New MySqlCommand(QUERY, CONN)
READER = COMMAND.ExecuteReader
While READER.Read
Chart20.Series("TEMP").Points.AddXY(READER.GetString("YValue"), READER.GetString("XValue"))
End While
CONN.Close()
Catch ex As Exception
CONN.Close()
MsgBox(ex.ToString, MsgBoxStyle.Critical)
End Try
Can you help me out pls

Answer 1

If you set the .Label, .Font, .LabelBackColor, and .LabelForeColor properties you can see the labels of the points, e.g. I put a Chart control on a Form with this code:
Imports System.Windows.Forms.DataVisualization.Charting
Public Class Form1
Class Datum
Property X As Integer
Property Y As Integer
Property Title As String
Sub New(x As Integer, y As Integer, t As String)
Me.X = x
Me.Y = y
Me.Title = t
End Sub
End Class
Sub ShowPointLabels()
Dim data = New List(Of Datum) From {New Datum(1, 1, "A"),
New Datum(2, 2, "B"),
New Datum(3, 3, "C")}
Chart1.Series.Clear()
Dim ds As New Series("Sample")
ds.ChartType = SeriesChartType.Point
Dim fnt = New Font("Arial", 12)
For Each d In data
Dim n = ds.Points.AddXY(d.X, d.Y)
Dim p = ds.Points(n)
p.Font = fnt
p.Label = d.Title
p.LabelBackColor = Color.PaleGoldenrod
p.LabelForeColor = Color.DarkBlue
p.LabelToolTip = "This is the label for " & d.Title
Next
Chart1.Series.Add(ds)
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
ShowPointLabels()
End Sub
End Class
To get this:
Also, it would be better to read all the data from the database in one step, in the next step add the data to the chart series, and finally add the series to the chart. That keeps the time that the connection to the database is open to a minimum and avoids the time taken to update the chart every time a point is added.

Answer 2

Sub ShowPointLabels()
Chart20.Series("TEMP").Points.Clear()
Try
CONN.Open()
COMMAND = CONN.CreateCommand
QUERY = "SELECT * FROM vitals"
COMMAND = New MySqlCommand(QUERY, CONN)
READER = COMMAND.ExecuteReader
For Each d In READER
Chart20.Series("TEMP").Points(Chart20.Series("TEMP").Points.AddXY(READER.GetString("XValue"), READER.GetString("YValue"))).Label = READER.GetString("Title")
Next
CONN.Close()
Catch ex As Exception
CONN.Close()
MsgBox(ex.ToString, MsgBoxStyle.Critical)
End Try
End Sub
I modified #Andrew Morton Answer to a simplified result and it works perfectly for me. I hope this helps somebody as well