各位下午好。
我正在处理一个使用WinForms VB.NET和MSSQL的项目，我需要使用SQLDependency来监视表中的新插入。在测试时我遇到了一个问题。启动应用程序后插入一次，我确实收到了插入了一些内容的通知，但在此之后，OnChange事件就不再被调用了。

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

如果您需要更多信息，我将适当更新我的问题