C#

#region Using directives

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Windows.Forms;
using System.Data.SqlClient;

#endregion

namespace NotifySample
{
    partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        SqlConnection con;
        SqlCommand cmd;
        SqlDependency dep;
        SqlDataAdapter da;
        DataTable dt;

        private void btnVeriCek_Click(object sender, EventArgs e)
        {
            con = new SqlConnection("data source=localhost;initial catalog=Dukkan;integrated security=SSPI");
            con.Open();
            cmd = new SqlCommand("Select DetayID,PersonelID,Ad,Soyad,Mail From dbo.PersonelDetay", con);
            dep = new SqlDependency(cmd);
               SqlDependency.Start("data source=localhost;initial catalog=Dukkan;integrated security=SSPI");
            dep.OnChange+=new OnChangeEventHandler(dep_OnChange);
            da = new SqlDataAdapter(cmd);
            dt = new DataTable();
            da.Fill(dt);
            dgVeriler.DataSource = dt;
        }

        void dep_OnChange(object sender, SqlNotificationEventArgs e)
        {
            MessageBox.Show("THIS AREA SQL INSERT, UPDATE, DELETED WANT TO SEE DATA");
//THIS AREA SQL INSERT, UPDATE, DELETED WANT TO SEE DATA
        }
    }
}

using System;
using ConsoleApplication1;

namespace extensionTestNamespace.test.com
{
    public static class ExtensionTest
    {
        public static String AAAAAAA<T>(this T x) where T : TestClass1
        {
            return "Extension Method Test";
        }
    }
}

using System;
using extensionTestNamespace.test.com;

namespace ConsoleApplication1
{
    public class TestClass1 { }
    public class TestClass2 { }
    public class TestClass3 { }


    class Program
    {
        private void run()
        {
            TestClass1 test1 = new TestClass1();
            TestClass2 test2 = new TestClass2();
            TestClass3 test3 = new TestClass3();

            //this works and I want it to work
            Console.WriteLine(test1.AAAAAAA());

            //this line won't compile, doesn't work, and
            //I want to add the same extension method 
            //to TestClass2 and don't know how
            Console.WriteLine(test2.AAAAAAA());     

            //this line won't compile either, but I
            //specifically don't want to add
            //the extension method to TestClass3
            Console.WriteLine(test3.AAAAAAA());     
        }


        static void Main(string[] args)
        {
            Program program = new Program();
            program.run();
        }
    }
}

public static String AAAAAAA<T>(this T x) 
    where T : TestClass1
    where T : TestClass2