I am working on these lists to get an item that matches the selected item from the combobox. 

```
private void InitializaMessageElement()
{
    if (_selectedTransactionWsName != null)
    {

```

1. get a transaction webservice name matching the selected item from the drop down here the output=TestWS which is correct

```
var getTranTypeWsName = TransactionTypeVModel
     .GetAllTransactionTypes()
     .FirstOrDefault(transTypes => 
             transTypes.WsMethodName == _selectedTransactionWsName);

```
2. Loop the list of wsnames from the treenode list. Here it gives me all the node I have which is correct.

```
var wsNameList = MessageElementVModel
     .GetAllTreeNodes().Select(ame => 
             ame.Children).ToList();//. == getTranTypeWsName.WsMethodName);

```
3. find the getTranTypeWsName.WsMethodName in the wsNameList. Here is where I have the problem:

```
      var msgElementList = wsNameList.Select(x => x.Where(ame => getTranTypeWsName != null && ame.Name == getTranTypeWsName.WsMethodName)).ToList();

```

my MsgElement list:

```
   _msgElementObsList = new ObservableCollection<MessageElementViewModel>(msgElementList);
    this.messageElements = _msgElementList;
    NotifyPropertyChanged("MessageElements");
}

```

Here it is throwing exception `Cannot convert from 'System.Collections.Generic.IEnumerable<System.Collections.Generic.IEnumerable to System.Collections.Generic.List).`