MultiSelectionKind SameType don't work for folders and files

Hi Benjamin,

The MultiSelectionKind="SameType" is a feature of the core TreeListBox control that compares the item being selected and the existing active item to ensure they are of the same .NET Type.  ShellTreeListBox inherits this functionality, however all items (folders and files) in the TreeListBox are wrapped with ShellObjectViewModel instances, so their Type is always the same.  That means that use of the SameType won't work for this scenario.

One idea I had to work around that might be to make a class that inherits ShellObjectViewModel named FolderShellObjectViewModel.  Then override the ShellObjectItemAdapter.CreateShellObjectViewModel.  If shellObject.Kind == ShellObjectKind.Folder, create and return an instance of FolderShellObjectViewModel instead.  Otherwise return the base method's result.  This would make the Types be different from folders and other things.  There are some other Kind values you might wish to lump into building a FolderShellObjectViewModel too, but that gives a general idea of one way to hopefully get it working how you wanted.

Thank you for your response, I followed your suggestion and the Types are now different for folders and other items. It's working as expected now.

However, I have an additional question, when I redefine the itemAdapter like this :

<shell:ShellTreeListBox.ItemAdapter>
    <model:NewShellObjectItemAdapter/>
</shell:ShellTreeListBox.ItemAdapter>

with this ItemAdapter : 

internal class NewShellObjectItemAdapter : ShellObjectItemAdapter
{
    protected override ShellObjectViewModel CreateShellObjectViewModel(TreeListBox ownerControl, IShellObject shellObject)
    {
        if(shellObject.Kind == ShellObjectKind.Folder)
        {
            return new FolderShellObjectViewModel(shellObject);
        }

        return base.CreateShellObjectViewModel(ownerControl, shellObject);
    }
}

I get an error (XDG0010) saying that it's not a valid value, but it still works. Do you know why ?

Thank you again for your help.

Hello,

If XDG0010 is a XAML designer error (I assume that's what XDG means), the Visual Studio designer is buggy and doesn't always recognize types properly.  If that's all it is and it's working at run-time, then everything in your code is fine and you should be able to safely ignore that error.  It will probably disappear as soon as you close the XAML file.