Can not Clear ListBox.Items

[Mike]

Hello,

I try to delete / clear the Items of a Listbox with

Me.datarowExtList.Clear()

But i get an NullReferenceException, since there are some Elements in the Listbox

I bind a ObservableCollection to the Itemsource Property of the LIstbox:

ItemsSource="{Binding datarowExtList}" SelectionMode="Single" DisplayMemberPath="DocDescription"

Private _datarowExtList As ObservableCollection(Of DataRowExt) = New ObservableCollection(Of DataRowExt)
    Public Property datarowExtList() As ObservableCollection(Of DataRowExt)
        Get
            Return _datarowExtList
        End Get
        Set(ByVal value As ObservableCollection(Of DataRowExt))
            _datarowExtList = value
            NotifyPropertyChanged("datarowExtList")
        End Set
    End Property

so - as i said, if there are no items in the Listbox shown up (ListBox.Items.Count = 0) i can do the Clear of the ObservableCollection.
But if there are any Items in the Listbox (just visual, neither in ListBox.Items or neither in my ObservableCollection) i get the NullReferenceException, on the Line of the ObservableCollection.CLear()

Whats wrong with the Listbox? what am i missing or doing wrong?

thanks for any advice

regards
Mike

[Vladi]

Hi,

As we see you have posted a support thread with ID: 686258 about the same issue could we continue the discussion there?

I will post our response from that thread in order for it to be available for the community:

We tried to reproduce the issue but to no avail.

I created and attached a sample project for you that shows there isn't any unexpected behavior when clearing the collection from the ViewModel.

All the best,
Vladi
the Telerik team

[Mike]

Hi,

I could solve my Problem - so you can also close my ticket (sorry for that)

the Problem was, that i accessed the ListBox, during SelectionChanged Event, and in some cases the ListBox was Null.
So i just had to handle that...


thanks & regards
Mike