Remove SelectedItem from TreeView

All previous answers will be helpful when you build the TreeView explicitly using TreeViewItem(s). If you need a solution to clear selection when using ItemsSource, use the following code:

private static TreeViewItem FindTreeViewSelectedItemContainer(ItemsControl root, object selection)
{
    var item = root.ItemContainerGenerator.ContainerFromItem(selection) as TreeViewItem;
    if (item == null)
    {
        foreach (var subItem in root.Items)
        {
            item = FindTreeViewSelectedItemContainer((TreeViewItem)root.ItemContainerGenerator.ContainerFromItem(subItem), selection);
            if (item != null)
            {
                break;
            }
        }
    }

    return item;
}

// Example:
private void Button_Click(object sender, RoutedEventArgs e)
{
    if (TV.SelectedItem != null)
    {
        var container = FindTreeViewSelectedItemContainer(TV, TV.SelectedItem);
        if (container != null)
        {
            container.IsSelected = false;
        }
    }
}

Not sure what you mean

If you want to remove the item, use this:

treeView1.Items.Remove(treeView1.SelectedItem);

If you want to remove the selection from the treeview, use this:

((TreeViewItem)treeView1.SelectedItem).IsSelected = false;

You want to unselect what is selected?

I think you want something like this:

((TreeViewItem)tv.SelectedItem).IsSelected = false;