Using OracleCommand to do query : Oracle « ADO.Net « C# / CSharp Tutorial

1. C# / CSharp Tutorial
2. ADO.Net
3. Oracle

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Data.OracleClient;

  public class Form1 : System.Windows.Forms.Form
  {
    private System.Windows.Forms.Button btnConnect;
    private System.Windows.Forms.Button btnRetrieve;
    private System.Windows.Forms.ListBox listJobs;

    public Form1()
    {
      this.btnConnect = new System.Windows.Forms.Button();
      this.btnRetrieve = new System.Windows.Forms.Button();
      this.listJobs = new System.Windows.Forms.ListBox();
      this.SuspendLayout();
      this.btnConnect.Location = new System.Drawing.Point(12, 28);
      this.btnConnect.Text = "C&onnect";
      this.btnConnect.Click += new System.EventHandler(this.btnConnect_Click);
      this.btnRetrieve.Location = new System.Drawing.Point(12, 64);
      this.btnRetrieve.Text = "&Retrieve";
      this.btnRetrieve.Click += new System.EventHandler(this.btnRetrieve_Click);
      this.listJobs.Font = new System.Drawing.Font("Courier New", 9F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));
      this.listJobs.ItemHeight = 15;
      this.listJobs.Location = new System.Drawing.Point(100, 28);
      this.listJobs.Size = new System.Drawing.Size(524, 244);
      this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
      this.ClientSize = new System.Drawing.Size(634, 284);
      this.Controls.Add(this.listJobs);
      this.Controls.Add(this.btnRetrieve);
      this.Controls.Add(this.btnConnect);
      this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.Fixed3D;
      this.MaximizeBox = false;
      this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
      this.Text = "TableDirect Sample";
      this.Load += new System.EventHandler(this.Form1_Load);
      this.ResumeLayout(false);

    }
    static void Main() 
    {
      Application.Run(new Form1());
    }

    private void btnConnect_Click(object sender, System.EventArgs e)
    {
      string connString = "User Id=hr; Password=demo; Data Source=oranet";
      if (oraConn.State != ConnectionState.Open)
      {
        try
        {
          oraConn.ConnectionString = connString;

          oraConn.Open();

          MessageBox.Show(oraConn.ConnectionString, "Successful Connection");
        }
        catch (Exception ex)
        {
          MessageBox.Show(ex.Message,"Exception Caught");
        }
      }
    }

    private OracleConnection oraConn;

    private void Form1_Load(object sender, System.EventArgs e)
    {
      oraConn = new OracleConnection();
    }

    private void btnRetrieve_Click(object sender, System.EventArgs e)
    {
      OracleCommand cmdEmployees = new OracleCommand();
      cmdEmployees.Connection = oraConn;
      cmdEmployees.CommandType = CommandType.Text;
      cmdEmployees.CommandText = "SELECT * FROM JOBS";
      string headText = "Job".PadRight(12);
      headText += "Title".PadRight(37);
      headText += "Min Salary".PadRight(12);
      headText += "Max Salary".PadRight(12);

      string headSep = "----";

      if (oraConn.State == ConnectionState.Open)
      {
        try
        {
          OracleDataReader dataReader = cmdEmployees.ExecuteReader();
          listJobs.Items.Add(headText);
          listJobs.Items.Add(headSep);
          string textLine = "";
          while (dataReader.Read())
          {
            textLine = dataReader.GetString(0);
            textLine += dataReader.GetString(1);
            textLine += dataReader.GetDecimal(2).ToString();
            textLine += dataReader.GetDecimal(3).ToString();

            listJobs.Items.Add(textLine);
          }
        }
        catch (Exception ex)
        {
          MessageBox.Show(ex.Message,"Exception Caught");
        }
      }

      cmdEmployees.Dispose();
    }
  }