Steema Central

Posted: **Wed Aug 08, 2007 10:07 pm**

Hello,

I'm having a strange problem with date-time data. I'm reading the data from a MySQL database and displaying it as a scatter plot. I can get the x-axis to display as numbers, but when I try to display dates, I get values in the 1900's. The actual data from the database displays properly (recent dates) in a gridview.

Here's my code...

Imports mysql.data.mysqlclient
Imports System.IO
Imports System.Data
Imports System.Windows

Partial Class Default2
Inherits System.Web.UI.Page
Protected Sub startup(ByVal sender As Object, ByVal e As System.EventArgs) Handles form1.Load

'Create the DataTable
Dim dt As New DataTable()
Dim myConnection As New MySqlConnection("server=egr3.egr.nau.edu;uid=wis_str_datt_usr;pwd=xxxxxx;database=wisard_streamed_data_test;")
Dim strSQL As String

'get the data into a datatable

strSQL = "SELECT * FROM streamed_data WHERE ProbeID = 20 AND SensorID = 104"
Dim myAdapter As New MySqlDataAdapter()
myAdapter.SelectCommand = New MySqlCommand(strSQL, myConnection)
myAdapter.Fill(dt)
'test binding to a gridview
'dgdata.DataSource = dt
'dgdata.DataBind()
'lets make a teechart!

Dim Point1 As New Steema.TeeChart.Styles.Points(WebChart1.Chart)
WebChart1.Chart.Axes.Bottom.Labels.DateTimeFormat = "yyyy/MM/dd"
Point1.YValues.DataMember = dt.Columns("measurement").ToString()
Point1.XValues.DateTime = dt.Columns("TimeStamp").DateTimeMode

Point1.DataSource = dt

End Sub

End Class

Posted: **Thu Aug 09, 2007 9:39 am**

Hi LordWhorfin

The problem can be that you have got the "DATE" values defined in the data base and you don't pass the DateTime values to the chart.

Could you try with below code:

Code: Select all

 private DataTable CreateDataSet()
        {

            #region Define Table
            DataTable DesperdicioMes = new DataTable();

            DataColumn DATE = new DataColumn("DATE", Type.GetType("System.DateTime"));
            DataColumn VALUES = new DataColumn("VALUES", Type.GetType("System.Double"));
            DataColumn LABELS = new DataColumn("LABELS", Type.GetType("System.String"));


            DesperdicioMes.Columns.Add(DATE);
            DesperdicioMes.Columns.Add(VALUES);
            DesperdicioMes.Columns.Add(LABELS);

            #endregion


            #region Populate Table
            DataRow dataRow;
            Random YVal = new Random();

            dataRow = DesperdicioMes.NewRow();
            dataRow[DATE] = DateTime.Parse("30/06/2007");
            dataRow[VALUES] = YVal.Next();
            dataRow[LABELS] = "";

            DesperdicioMes.Rows.Add(dataRow);

            for (int i = 1; i < 31; i++)
            {

                dataRow = DesperdicioMes.NewRow();
                dataRow[DATE] = DateTime.Parse(i.ToString() + "/07/2007");
                dataRow[VALUES] = YVal.Next();
                dataRow[LABELS] = "";

                DesperdicioMes.Rows.Add(dataRow);
            }


            dataRow = DesperdicioMes.NewRow();
            dataRow[DATE] = DateTime.Parse("01/08/2007");
            dataRow[VALUES] = YVal.Next();
            dataRow[LABELS] = "";

            DesperdicioMes.Rows.Add(dataRow);

            #endregion

            return DesperdicioMes;
        }



        private void Form1_Load(object sender, System.EventArgs e)
        {
            line1.XValues.DateTime = true;
            tChart1.Axes.Bottom.Labels.DateTimeFormat = "dd/MM/yyyy";
            tChart1.Axes.Bottom.Labels.Angle = 90;


            line1.Clear();
            line1.DataSource = CreateDataSet();
            line1.YValues.DataMember = "VALUES";
            line1.XValues.DataMember = "DATE";
            line1.LabelMember = "LABELS";

            line1.CheckDataSource();
        }

It's a C# code but if you need you can convert it to VB.NET

Steema Central

weird datetime problem

weird datetime problem