Mitsubishi Electric MELSEC iQ-R-R00CPU - Page 259

13 DATABASE FUNCTION
13.3 CPU Module Database Access (from External Device) Function
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■Source code of the sample program
The following describes the source code of the sample program.
• Development environment: Visual Studio 2015
• Programming language: C#
namespace iQ_R_DB_Access
{
public partial class FrmMain : Form
{
public FrmMain()
{
InitializeComponent();
// Range setting of X-/Y-axis on a graph
chart1.ChartAreas[0].AxisX.Minimum = 400;
chart1.ChartAreas[0].AxisX.Maximum = 600;
chart1.ChartAreas[0].AxisY.Minimum = 400;
chart1.ChartAreas[0].AxisY.Maximum = 600;
// Initial value (all) set to the judge value of search target
cmbJudge.SelectedIndex = 2;
}
/// <summary>
/// Operation when the Search button is clicked
/// Records that match the judge value specified by the combo box are acquired and displayed in a list and a scatter plot of X and Y field values.
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnSearch_Click(object sender, EventArgs e)
{
// The number of fields (the number of fields on the CheckData table)
int len = 6;
// Acquiring the data source name
string strConnect = txtDataSourceName.Text.ToString();
// ODBC connection information management class
OdbcConnectionStringBuilder o = new OdbcConnectionStringBuilder();
o.Dsn = strConnect;
// Creating the connection object
OdbcConnection cn = new OdbcConnection(o.ConnectionString);
// SQL statement
string strQuery = GetSQL();
// Creating the command object
OdbcCommand cmd = new OdbcCommand(strQuery, cn);
// Initializing the list
dtRecord.Rows.Clear();
// Initializing the graph
chart1.Series[0].Points.Clear();
try
{
// Connecting to DB
cn.Open();
// Creating the data reader object
OdbcDataReader reader = cmd.ExecuteReader();