SQLDependency stops receiving notifications after 1 notification - sql-server

Question

Good afternoon everyone.
I am working on a project that uses WinForms VB.NET and MSSQL I have a requirement to use SQLDependency to monitor a table for new inserts. I have encountered a problem while testing it out. Inserting once after starting the application and I do receive the notification that something has been inserted, but after that the OnChange event just doesn't get called anymore.
Private Sub LoadOrder()
Dim objError As New AppFramework.Logging.EventLog
Dim objQuoOrders As New QuotationOrders.QuotationOrder
Try
objQuoOrders.Companyid = SystemCompanyId
objQuoOrders.Picker = GsUserName
objQuoOrders.InvType = "O"
ThreadSafe(Sub() gcOrders.DataSource = objQuoOrders.GetOrdersByPicker())
Catch ex As Exception
MessageBox.Show(ex.Message, "LoadOrder", MessageBoxButtons.OK, MessageBoxIcon.Error)
objError.LogError(SystemApplicationLogSource, "AceFinancials", ex)
End Try
End Sub
Private Sub ActivateDependency()
Dim objError As New AppFramework.Logging.EventLog
Try
If sqlConnection IsNot Nothing AndAlso sqlConnection.State = ConnectionState.Open Then sqlConnection.Close()
sqlConnection = New SqlConnection(AppFramework.Database.Connection.ConnectionString)
sqlConnection.Open()
SqlDependency.Stop(AppFramework.Database.Connection.ConnectionString)
SqlDependency.Start(AppFramework.Database.Connection.ConnectionString)
Using cmd As SqlCommand = New SqlCommand(" Select tb_quotation_notifications.notification_id, tb_quotation_notifications.notification_invid
From dbo.tb_quotation_notifications
Where tb_quotation_notifications.notification_picker_id = " & UserID &
" And tb_quotation_notifications.company_id = " & SystemCompanyId, sqlConnection)
Dim dependency As SqlDependency = New SqlDependency(cmd)
AddHandler dependency.OnChange, AddressOf dependency_OnChange
cmd.ExecuteNonQuery()
End Using
Catch ex As Exception
MessageBox.Show(ex.Message, "ActivateDependency", MessageBoxButtons.OK, MessageBoxIcon.Error)
objError.LogError(SystemApplicationLogSource, "AceFinancials", ex)
End Try
End Sub
Private Sub dependency_OnChange(sender As Object, e As SqlNotificationEventArgs)
Dim objError As New AppFramework.Logging.EventLog
Try
If e.Info = SqlNotificationInfo.Insert Then
NotificationManager.ShowNotification(NotificationManager.Notifications(0))
LoadOrder()
ActivateDependency()
End If
Catch ex As Exception
MessageBox.Show(ex.Message, "dependency_OnChange", MessageBoxButtons.OK, MessageBoxIcon.Error)
objError.LogError(SystemApplicationLogSource, "AceFinancials", ex)
End Try
End Sub
Private Sub ThreadSafe(method As MethodInvoker)
Dim objError As New AppFramework.Logging.EventLog
Try
If (InvokeRequired) Then
Invoke(method)
Else
method()
End If
Catch ex As Exception
MessageBox.Show(ex.Message, "ThreadSafe", MessageBoxButtons.OK, MessageBoxIcon.Error)
objError.LogError(SystemApplicationLogSource, "AceFinancials", ex)
End Try
End Sub
If you need any more info I will update my question appropriately

Answer 1

I found out what the problem was with the big help of Dan Guzman.
After the OnChange event fires you need to remove the event handler and then subscribe to the event again, unlike what I was doing and that is stoping the SqlDependency and starting it again.
In my case I have done that as follows
OnChange Event
Private Sub dependency_OnChange(sender As Object, e As SqlNotificationEventArgs)
Dim objError As New AppFramework.Logging.EventLog
Try
If e.Info = SqlNotificationInfo.Insert Then
NotificationManager.ShowNotification(NotificationManager.Notifications(0))
LoadOrder()
End If
Dim dependency As SqlDependency = sender
RemoveHandler dependency.OnChange, AddressOf dependency_OnChange
ActivateDependency()
Catch ex As Exception
MessageBox.Show(ex.Message, "dependency_OnChange", MessageBoxButtons.OK, MessageBoxIcon.Error)
objError.LogError(SystemApplicationLogSource, "AceFinancials", ex)
End Try
End Sub
Subscribing event
Private Sub ActivateDependency()
Dim objError As New AppFramework.Logging.EventLog
Try
If sqlConnection IsNot Nothing AndAlso sqlConnection.State = ConnectionState.Open Then sqlConnection.Close()
sqlConnection = New SqlConnection(AppFramework.Database.Connection.ConnectionString)
sqlConnection.Open()
Using cmd As SqlCommand = New SqlCommand(" Select tb_quotation_notifications.notification_id, tb_quotation_notifications.notification_invid
From dbo.tb_quotation_notifications
Where tb_quotation_notifications.notification_picker_id = " & UserID &
" And tb_quotation_notifications.company_id = " & SystemCompanyId, sqlConnection)
Dim dependency As SqlDependency = New SqlDependency(cmd)
AddHandler dependency.OnChange, AddressOf dependency_OnChange
Using sqlReader As SqlDataReader = cmd.ExecuteReader
End Using
End Using
Catch ex As Exception
MessageBox.Show(ex.Message, "ActivateDependency", MessageBoxButtons.OK, MessageBoxIcon.Error)
objError.LogError(SystemApplicationLogSource, "AceFinancials", ex)
End Try
End Sub
Thanks a lot have a nice day.
Edit:
I moved the SqlDependency.Start() in the form load function, and the stop in the form closing function