using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.OleDb;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace wdemo
{
    public partial class login : Form
    {
        public login()
        {
            InitializeComponent();
        }
            String name, pwd;
        private void button1_Click_1(object sender, EventArgs e)
        {
            //資料來源
            string connString = " Provider = OraOLEDB.Oracle.1; Data Source = (DESCRIPTION = (CID = GTU_APP)(ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 127.0.0.1)(PORT = 1521)))(CONNECT_DATA = (SID = ORCL)(SERVER = ORCL))); User Id = system;Password = sys";
            OleDbConnection conn = new OleDbConnection(connString);//例項化連線物件
            conn.Open();//開啟連線
           
            OleDbCommand cmdd = conn.CreateCommand();
            cmdd.CommandText = "select * from userinfo where name = '" + this.TextName.Text + "' and pwd = '" + this.textPwd.Text + "'";
            OleDbDataReader oleRead = cmdd.ExecuteReader();//注意表在哪個使用者下

            //測試連線oracle資料庫
            //try{
            //    conn.Open();
            //    MessageBox.Show("連線成功");
            //}
            //catch (Exception ex){
            //    MessageBox.Show("失敗了哦");
            //}
            //finally{
            //    conn.Close();
            //}

            try
            {
                while (oleRead.Read())
                {
                     name = oleRead["name"].ToString();
                     pwd = oleRead["pwd"].ToString();
                }
                if (this.TextName.Text.Trim() == name.Trim() && this.textPwd.Text.Trim() == pwd.Trim())
                {
                    MessageBox.Show("歡迎登入HIS醫院資訊系統！ ", "SUCCESS");
                    Show sw = new Show();//跳轉窗體
                    sw.Show();
                }
                else
                {
                    MessageBox.Show("您的使用者名稱或密碼不正確！ ", "ERROR");
                }
            }
            catch{
                MessageBox.Show("資料庫無法連線!");
            }finally{
                conn.Close();//關閉連線
            }
        }

        private void reset_Click(object sender, EventArgs e)
        {
            TextName.Text = "";
            textPwd.Text = "";
            TextName.Focus();
        }

    }   
}
 

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.OleDb;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace wdemo
{
    public partial class Show : Form
    {
        public Show()
        {
            InitializeComponent();

            string connection = " Provider = OraOLEDB.Oracle.1; Data Source = (DESCRIPTION = (CID = GTU_APP)(ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 127.0.0.1)(PORT = 1521)))(CONNECT_DATA = (SID = ORCL)(SERVER = ORCL))); User Id = system;Password = sys";//資料庫的連線 資料來源 使用者 密碼
            OleDbConnection coon = new OleDbConnection(connection);//建立資料庫連線

            OleDbCommand cmd = new OleDbCommand("select * from userinfo",coon);//執行資料連線    如果想選某兩個列可將*改為name,pwd 即 “select name,pwd from userinfo”

            DataSet ds1;
            ds1 = new DataSet();//定義資料集

            OleDbDataAdapter da1 = new OleDbDataAdapter(cmd);//取出資料表
            da1.Fill(ds1);//將資料載入到資料集中

            DataTable dt = ds1.Tables[0];//將資料放入表中

            coon.Close();//關閉資料庫連線

            //遍歷
            // //表為空則返回
            //下面的程式碼可對錶進行操作 如果想直接顯示可直接加上資料顯示程式碼  下面的if  else程式碼就不用了
            if (dt == null)
            {
                return;
            }
            else
            {
                for (int i = 0; i < dt.Rows.Count; i++)
                {

                }
            }
            //資料顯示 在dataGridView中顯示
            this.dataGridView1.DataSource = dt.DefaultView;
            this.dataGridView1.Refresh();
        }
   
     }  
}