Handlers and Grouping disappears after database update

[Martin Gartmann]

Dear readers,

i have a scheduler grouped by resources. I use a dropdown (selectionmode=Multisimple) to switch the resources on/off to show them side by side in the scheduler and AddHandler to each item in the dropdown.

In Form_Load() i use the following code

      

' Populates the dropdown


ddlResourcen.DataSource = SchedulerDataDataSet.Resources

ddlResourcen.ValueMember = "ID"

ddlResourcen.DisplayMember = "Name"

 

 

For Each item As RadListDataItem In Me.ddlResourcen.Items

    AddHandler item.RadPropertyChanged, AddressOf SelectedChanged

Next

 

Here is the code for SelectedChanged()

Private Sub SelectedChanged()
       AddResources()
   End Sub

It simply switch the resources on/off.

I can move appointment between resources, move and resize them and all is fine, until i try to save it to the database.

I use just the code suggested in the demos with just one change to show my resources in different colors at the last line

When i call the Sub UpdateDB the stored appointments/resources data is correct, but my handlers for to the drowdown items are not longer

working and just one resource is visible because my multi preselection is gone.

    Private Sub UpdateDB()
        AppointmentsResourcesTableAdapter.Adapter.AcceptChangesDuringUpdate = False
        Dim deletedRelationRecords As schedulerDataDataSet.AppointmentsResourcesDataTable = TryCast(Me.SchedulerDataDataSet.AppointmentsResources.GetChanges(DataRowState.Deleted), schedulerDataDataSet.AppointmentsResourcesDataTable)
        Dim newRelationRecords As schedulerDataDataSet.AppointmentsResourcesDataTable = TryCast(Me.SchedulerDataDataSet.AppointmentsResources.GetChanges(DataRowState.Added), schedulerDataDataSet.AppointmentsResourcesDataTable)
        Dim modifiedRelationRecords As schedulerDataDataSet.AppointmentsResourcesDataTable = TryCast(Me.SchedulerDataDataSet.AppointmentsResources.GetChanges(DataRowState.Modified), schedulerDataDataSet.AppointmentsResourcesDataTable)
        Dim newAppointmentRecords As schedulerDataDataSet.AppointmentsDataTable = TryCast(Me.SchedulerDataDataSet.Appointments.GetChanges(DataRowState.Added), schedulerDataDataSet.AppointmentsDataTable)
        Dim deletedAppointmentRecords As schedulerDataDataSet.AppointmentsDataTable = TryCast(Me.SchedulerDataDataSet.Appointments.GetChanges(DataRowState.Deleted), schedulerDataDataSet.AppointmentsDataTable)
        Dim modifiedAppointmentRecords As schedulerDataDataSet.AppointmentsDataTable = TryCast(Me.SchedulerDataDataSet.Appointments.GetChanges(DataRowState.Modified), schedulerDataDataSet.AppointmentsDataTable)
        Try
            If newAppointmentRecords IsNot Nothing Then
                Dim newAppointmentIds As New Dictionary(Of Integer, Integer)()
                Dim oldAppointmentIds As New Dictionary(Of Object, Integer)()
                For i As Integer = 0 To newAppointmentRecords.Count - 1
                    oldAppointmentIds.Add(newAppointmentRecords(i), newAppointmentRecords(i).ID)
                Next
                AppointmentsTableAdapter.Update(newAppointmentRecords)
                For i As Integer = 0 To newAppointmentRecords.Count - 1
                    newAppointmentIds.Add(oldAppointmentIds(newAppointmentRecords(i)), newAppointmentRecords(i).ID)
                Next
                If newRelationRecords IsNot Nothing Then
                    For i As Integer = 0 To newRelationRecords.Count - 1
                        newRelationRecords(i).AppointmentID = newAppointmentIds(newRelationRecords(i).AppointmentID)
                    Next
                End If
            End If
            If deletedRelationRecords IsNot Nothing Then
                AppointmentsResourcesTableAdapter.Update(deletedRelationRecords)
            End If
            If deletedAppointmentRecords IsNot Nothing Then
                AppointmentsTableAdapter.Update(deletedAppointmentRecords)
            End If
            If modifiedAppointmentRecords IsNot Nothing Then
                AppointmentsTableAdapter.Update(modifiedAppointmentRecords)
            End If
            If newRelationRecords IsNot Nothing Then
                AppointmentsResourcesTableAdapter.Update(newRelationRecords)
            End If
            If modifiedRelationRecords IsNot Nothing Then
                AppointmentsResourcesTableAdapter.Update(modifiedRelationRecords)
            End If
            Me.SchedulerDataDataSet.AcceptChanges()
        Catch ex As Exception
            MessageBox.Show(String.Format("An error occurred during the update process:" & vbLf & "{0}", ex.Message))
        Finally
            If deletedRelationRecords IsNot Nothing Then
                deletedRelationRecords.Dispose()
            End If
            If newRelationRecords IsNot Nothing Then
                newRelationRecords.Dispose()
            End If
            If modifiedRelationRecords IsNot Nothing Then
                modifiedRelationRecords.Dispose()
            End If
        End Try

        AddResources()
    End Sub

    Private Sub AddResources()

        Me.rscMain.Resources.Clear()
        Dim i As Integer = 0

        For Each Row As DataRow In SchedulerDataDataSet.Tables("Resources").Rows
            Dim resource As New Resource()
            resource.Id = New EventId(i + 1)
            resource.Name = Row("Name").ToString
            resource.Color = Color.FromName(Row("SystemColor"))

            If ddlResourcen.Items(i).Selected = True Then
                Me.rscMain.Resources.Add(resource)
            End If

            i = i + 1
        Next

        Me.rscMain.GroupType = GroupType.Resource
        Me.rscMain.ActiveView.ResourcesPerView = 4
    End Sub

 

I belive this takes places because the SchedulerDataDataSet was changed, because when i reuse the code

' Populates the dropdown
ddlResourcen.DataSource = SchedulerDataDataSet.Resources
ddlResourcen.ValueMember = "ID"
ddlResourcen.DisplayMember = "Name"


For Each item As RadListDataItem In Me.ddlResourcen.Items
    AddHandler item.RadPropertyChanged, AddressOf SelectedChanged
Next

i can again use it, but my preselection is gone, of course.

Any suggestions how to stop this behaviour.

Kind regards

Martin Gartmann

[Dess | Tech Support Engineer, Principal]

Hello Martin,

Thank you for writing.

According to the provided code snippet, you set the RadDropDownList.DataSource property to the Resources collection and subscribe to the RadPropertyChanged event for each item in the drop down. However, when saving to the database, you clear the resources and add new ones. Thus, new items to RadDropDownList are added. Hence, you should subscribe to the RadPropertyChanged event for each of the new items.

I hope this information helps. Should you have further questions I would be glad to help.

 Regards,
Dess
Telerik

[Martin Gartmann]

Dear Dess,

i solved the case by population the dropdown via a datatable build from another dataset and not the ResourcesCollection. Changing a Resource or Adding a new entry in the Resources Table in the database is a rare case in my app and if this happens i will reload them.

      Me.ResourcesTA.Fill(Me.DsResourcen.Resources)
   
' Baut die Resourcenauswahl auf

     ddlResourcen.DataSource = ResourcesTA.GetData

     ddlResourcen.ValueMember = "ID"

     ddlResourcen.DisplayMember = "Name"

Kind regards

Martin