App crashes when trying to bind a list of strings to LongListMultiSelector

Question

I'm getting a weird error when I'm trying to bind a list of strings to the LongListMultiSelector. The values I want to assign are from the IsolatedStorage.GetFileNames("Path\\*");

XAML-Code: The Template

               <DataTemplate x:Key="plItemTemplate">
            <Grid Margin="{StaticResource PhoneTouchTargetOverhang}">
                <toolkit:ContextMenuService.ContextMenu>
                    <toolkit:ContextMenu Name="conPlMgr" Opened="conPlMgr_Opened" Closed="conPlMgr_Closed">
                        <toolkit:MenuItem Name="mnuPlaylist" Header="{Binding LocalizedResources.AddToPlaylist, Source={StaticResource LocalizedStrings}}" Click="mnuPlaylist_Click"/>
                        <toolkit:MenuItem Name="mnuFav" Header="{Binding LocalizedResources.AddToFav, Source={StaticResource LocalizedStrings}}" Click="mnuFav_Click"/>
                    </toolkit:ContextMenu>
                </toolkit:ContextMenuService.ContextMenu>
                <TextBlock Name="cmdPlItem" Tap="cmdPlItem_Tap" FontFamily="Segoe UI Symbol" TextWrapping="Wrap" Margin="5,0,5,5" FontSize="24"/>
            </Grid>
        </DataTemplate>

The LongListMultiSelector
        <Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
            <Grid Style="{StaticResource LongListLastItemMargin}">
                <toolkit:LongListMultiSelector
                    Name="lstPlaylists"
                    Style="{StaticResource LongListMultiselectorProps}"
                    ItemTemplate="{StaticResource plItemTemplate}"
                    ItemsSource="{Binding Instance.GetPlaylists,Source={StaticResource PlaylistManager}}"
                    IsSelectionEnabledChanged="lstPlaylists_IsSelectionEnabledChanged"/>
            </Grid>
        </Grid>

The List:

public List<string> GetPlaylists
{
    get { return isoStore.GetFileNames("Playlists\\*").ToList(); }
}

And this is the error message I get:

Message: Error HRESULT E_FAIL has been returned from a call to a COM component. StackTrace:  Is handled?: False e.ToString()
System.Windows.ApplicationUnhandledExceptionEventArgs CompleteStuff: MS.Internal.WrappedException: Error HRESULT E_FAIL has been returned from a call to a COM component. ---> System.Exception: Error HRESULT E_FAIL has been returned from a call to a COM component. at MS.Internal.XcpImports.CheckHResult(UInt32 hr) at MS.Internal.XcpImports.FrameworkElement_MeasureOverride(FrameworkElement element, Size availableSize) at System.Windows.FrameworkElement.MeasureOverride(Size availableSize)
at System.Windows.FrameworkElement.MeasureOverride(IntPtr nativeTarget, Double inWidth, Double inHeight, Double& outWidth, Double& outHeight) --- End of inner exception stack trace ---

I don't get what's the problem here, there should be no problem with the values, they're returned correctly. I've binged and googled so much but still weren't able to find a solution for this, it's so depressing since this is such a blocker for a new feature...

UPDATE Well~ I don't know but it works now. If I do this: <TextBlock Text={Binding} /> it works if I set the values in the constructor.

I think that LongListMultiSelector is trying to get the items too early. Try to move itemsSource initialization to the page constructor. — crea7or
I already tried this. I set the ItemSource-Property in the Constructor, in the Loaded-Event, or even in an own method which was called in the constructor, but nothing worked I got in all cases the same error. — klose91

crea7or crea7or · Accepted Answer · 2014-01-13T12:12:37

Try to make a list as the member of the class:

add member of the class:

private List <string> filesList = new List<string>();

...

change the function:

public void GetPlaylists
{
   filesList = isoStore.GetFileNames("Playlists\\*").ToList();
   LongListMultiSelectorName.itemsSource = filesList;
}

call GetPlaylists where you want.

App crashes when trying to bind a list of strings to LongListMultiSelector

1 Answers