CODEWITHSUNDEEP
listviewwin-universal-app
Geert van Horrik
Geert van Horrik

Reputation: 5724

How to clear selection on a virtualized ListView in UWP?

I am in doubt. I have a large list container possibly thousands of items. When I virtualize (which is almost a demand for performance), I get this exception as soon as I try to update the selection:

Failed to update selection | [Exception] System.Exception: Catastrophic failure (Exception from HRESULT: 0x8000FFFF (E_UNEXPECTED))
   at System.Runtime.InteropServices.WindowsRuntime.IVector`1.RemoveAt(UInt32 index)
   at System.Runtime.InteropServices.WindowsRuntime.VectorToListAdapter.RemoveAtHelper[T](IVector`1 _this, UInt32 index)
   at System.Runtime.InteropServices.WindowsRuntime.VectorToListAdapter.RemoveAt[T](Int32 index)
   at MyApp.Views.SearchView.<>c__DisplayClass9_0.<UpdateListViewSelection>b__0()
   at MyApp.Views.SearchView.<>c__DisplayClass10_0.<<ExecuteSafely>b__0>d.MoveNext()

I tried clearing the selection in 2 ways:

A: 

listView.SelectedItems.Clear();

B:

for (int i = 0; i < listView.SelectedItems.Count; i++)
{
    listView.SelectedItems.RemoveAt(i--);
}

The alternative is not to virtualize, but that's even worse... Anyone knows how to safely clear the selection on a virtualized listview in UWP?

Upvotes: 4

Views: 1207

Answers (1)

Geert van Horrik
Geert van Horrik

Reputation: 5724

It seems important to clear the right way based on the SelectionMode of the ListView. Below is a safe way to clear the selection of a ListView (without having to care about the SelectionMode yourself):

public static void ClearSelection(this ListViewBase listView)
{
    Argument.IsNotNull(() => listView);

    switch (listView.SelectionMode)
    {
        case ListViewSelectionMode.None:
            break;

        case ListViewSelectionMode.Single:
            listView.SelectedItem = null;
            break;

        case ListViewSelectionMode.Multiple:
        case ListViewSelectionMode.Extended:
            listView.SelectedItems.Clear();
            break;

        default:
            throw new ArgumentOutOfRangeException();
    }
}

Upvotes: 6

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