error - Unable to cast object of type, wpf Listview

Question

Hello everyone,

 

After bind listview with linq query, occuring error. 

 

how can I solve this error ? Unable to cast object of type 'Grouping[System.String,<>

public UC_ArcMgmt()
       {
           InitializeComponent();
           DMSBusinessLayer service = new DMSBusinessLayer();
           listView1.ItemsSource = service.GetArchivedList().SelectMany((x) => new[] { new { Id = x.Id, ArchievedName = x.ArchievedName, UpdatedDate = x.UpdatedDate, FileSize = FormatBytes(x.fsize), docCount = x.docCount } }).Distinct()
GroupBy((x) => x.ArchievedName);
       }   private void btn_Click(object sender, MouseButtonEventArgs e)
        {
foreach (Tble_Documents item in listView1.SelectedItems) /*here showing error*/
                        {
                            int DocId = Convert.ToInt32(item.Id);
}
}