Question

I am using LongListSelector control with ItemRealized Event and its working fine but when I update the list which is assigned to ItemSource of LongListSelector the items in LongListSelector are not updating.

Below is the code I am using in XAML.

<phone:LongListSelector SelectionChanged="listBoxGroups_SelectionChanged_1" Grid.Row="1" x:Name="longListSelector" ItemTemplate="{StaticResource groupsItemTemplate}" Margin="0,100,0,0">
</phone:LongListSelector>

In code behind.

 public GroupsMainPage()
 {
        InitializeComponent();
        longListSelector.ItemRealized += longListSelector_ItemRealized;
        this.Loaded += GroupsMainPage_Loaded; 
 }


void longListSelector_ItemRealized(object sender, ItemRealizationEventArgs e)

    {
        if (!controller.IsLoading && longListSelector.ItemsSource != null && longListSelector.ItemsSource.Count >= 100)
        {
            if (e.ItemKind == LongListSelectorItemKind.Item)
            {
                if ((e.Container.Content as Result).Equals(longListSelector.ItemsSource[longListSelector.ItemsSource.Count -7]))
                {
                    connectToWebService();

                }
            }
        }
    }

After receiving the response from web service I simply do the following.

private void WebServiceSuccessAction(Object obj)
{
    GroupModel.getInstance().GetGroupResponse((GroupResponse)obj);
    if (GroupModel.getInstance().GetGroupResponse().Response.errorCode == 0)
    {
         controller = new GroupController();
         if (fetchNumberofGroups <= 100)
         {
              this.ResultList = controller.GetGroupList();
              longListSelector.ItemsSource = this.ResultList;

         }
         else
         {
              controller.addNewGroupData();
              this.ResultList = controller.GetGroupList();

         }
    }
    else
    {
         List<Error> error = ConfigModel.getInstance().getConfigResponse().Response.data.errors;
         foreach (Error err in error)
         {
             if (err.code == GroupModel.getInstance().GetGroupResponse().Response.errorCode)
             {
                MessageBox.Show(err.text);
             }
         }
    }
}

Answer 1

I have find out the solution my self. Problem was
controller.addNewGroupData();
this.ResultList = controller.GetGroupList();

should be in

Deployment.Current.Dispatcher.BeginInvoke(() =>
                    {});block

i-e.

Deployment.Current.Dispatcher.BeginInvoke(() =>
                    {
                        controller.AddNewGroupData();
                        this.ResultList = controller.GetGroupList();
                    });

Its working fine now. I researched alot but this block was not mentioned on any website except microsoft(twitter example).