基于ORACLE的事件通知示例代码( ORACLE DEPENDECY)

基于ORACLE的事件通知

using Oracle.DataAccess.Client;using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Windows.Forms;namespace WindowsFormsApplication1{ public partial class Form1 : Form { OracleDependency dep; OracleConnection conn; public Form1() { InitializeComponent(); //设置App的监听端口，即使用哪个端口接收Change Notification。 OracleDependency.Port = 49501; string cs = "User Id = hiip; Password=hiip;Data Source = (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.10.3)(PORT = 1521)))(CONNECT_DATA = (SERVICE_NAME = orcl)))"; conn = new OracleConnection(cs); conn.Open(); } // private void btnReg_Click(object sender, EventArgs e) { if (dep == null || !dep.IsEnabled) { OracleCommand cmd = new OracleCommand("select * from userinfo", conn); //绑定OracleDependency实例与OracleCommand实例 dep = new OracleDependency(cmd); //指定Notification是object-based还是query-based，前者表示表（本例中为tab_cn）中任意数据变化时都会发出Notification；后者提供更细粒度的Notification，例如可以在前面的sql语句中加上where子句，从而指定Notification只针对查询结果里的数据，而不是全表。 //dep.QueryBasedNotification = false; //dep.QueryBasedNotification = true; //是否在Notification中包含变化数据对应的RowId //dep.RowidInfo = OracleRowidInfo.Include; //指定收到Notification后的事件处理方法 dep.OnChange = new OnChangeEventHandler(OnNotificaton); //是否在一次Notification后立即移除此次注册 cmd.Notification.IsNotifiedOnce = false; //此次注册的超时时间（秒），超过此时间，注册将被自动移除。0表示不超时。 cmd.Notification.Timeout = 0; //False表示Notification将被存于内存中，True表示存于数据库中，选择True可以保证即便数据库重启之后，消息仍然不会丢失 cmd.Notification.IsPersistent = true; // cmd.ExecuteNonQuery(); // rtb1.AppendText("Registration completed. " DateTime.Now.ToLongTimeString() Environment.NewLine); } } private void btnUnreg_Click(object sender, EventArgs e) { //注销 if (dep.IsEnabled) { dep.RemoveRegistration(conn); rtb1.AppendText("Registration Removed. " DateTime.Now.ToLongTimeString() Environment.NewLine); } } private void OnNotificaton(object src, OracleNotificationEventArgs arg) { //可以从arg.Details中获得通知的具体信息，比如变化数据的RowId DataTable dt = arg.Details; //...... rtb1.BeginInvoke( new Action(() => { rtb1.AppendText("Notification Received. " DateTime.Now.ToLongTimeString() " Changed data(rowid): " arg.Details.Rows[0]["rowid"].ToString() Environment.NewLine); })); } }}