SqlDependency OnChange Event Fires Repeatedly

I am using the SqlDependency to notify me of data changes in a table. However, as soon as I start it, the OnChange event fires over and over even though no data has changed.

Essentially All I want to do is be notified when records are inserted into a table. I am able to get another example to work using a Service Broker Queue and a sql query of WAITFOR ( RECEIVE CONVERT(int, message_body) AS msg FROM QueueMailReceiveQueue ) However I would prefer not to use a queue for once my messages have been read they are taken off the queue and I would rather control that manually.

Any help with getting SqlDependency to notify my app when records are added and not over and over when the data has changed would be great.

Here is my code:




Code Snippet
public partial class Form1 : Form {


public static event OnChangeEventHandler OnChange;
string _strConnString = "Data Source=localhost;Integrated Security=SSPI;Initial Catalog=email_queue;Pooling=False;";
string _strSql = "SELECT email_id from email where isprocessed = 0";
private DataSet dataToWatch = null;
private SqlConnection connection = null;
private SqlCommand command = null;
SqlDependency dependency = null;
SqlDataReader sdr = null;


public Form1() {


InitializeComponent();
}

private void button1_Click(object sender, EventArgs e) {

SqlDependency.Stop(_strConnString);
SqlDependency.Start(_strConnString);
if (connection == null) {

connection = new SqlConnection(_strConnString);
connection.Open();
}
if (command == null) {

command = new SqlCommand(_strSql, connection);
}
if (dataToWatch == null) {

dataToWatch = new DataSet();
}
GetData();
}

private void GetData() {

dataToWatch.Clear();
command.Notification = null;
dependency = new SqlDependency(command);
dependency.OnChange += new OnChangeEventHandler(dependency_OnChange);
command.CommandTimeout = 400;
using (SqlDataAdapter adapter = new SqlDataAdapter(command)) {

adapter.Fill(dataToWatch, "email");
}
}

private void dependency_OnChange(object sender, SqlNotificationEventArgs e) {

ISynchronizeInvoke i = (ISynchronizeInvoke)this;
if (i.InvokeRequired) {

OnChangeEventHandler tempDelegate = new OnChangeEventHandler(dependency_OnChange);
object[] args = { sender, e };
i.BeginInvoke(tempDelegate, args);
return;
}
dependency = (SqlDependency)sender;
dependency.OnChange -= dependency_OnChange;
this.Text = DateTime.Now.ToString();
GetData();
}

private void Form1_FormClosed(object sender, FormClosedEventArgs e) {

SqlDependency.Stop(_strConnString);
if (connection != null) {

connection.Close();
}
}
}